Chemical defenses/toxicity in clown loach

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andyroo
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Chemical defenses/toxicity in clown loach

Post by andyroo » Wed Jan 11, 2006 10:10 am

Loach Listers,

What do you know about the toxicity or chemical defenses in clown
loaches? In University i kept a hard-core predator tank (as you
do as a macho youth) with big oscar, arawana, eels, snake-head,
leaf-fish, clown knife and other toothy horrors, and a pair of little
4cm (<2 inch) clowns. I'd watch the arawana go in for a taste, then back
off at the last moment. In three years they didn't grow much and didn't
have any drama with their tank-mate monsters either.

It makes sense with the bold coloration that they have chemical
defenses, but i can't find any literature on it.

Suggestions?


Andyroo
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JD
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Post by JD » Wed Jan 11, 2006 11:26 am

I have never heard of chemical weapons, but they do have the big suborbital spines. Maybe the Arawana tasted the orange delight once, and after receiving a mouth full of hurt, second guessed himself subsequent times.

JD

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Martin Thoene
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Post by Martin Thoene » Wed Jan 11, 2006 11:34 am

Hi andyroo, and a big welcome to Loaches Online :)

In all the time I've spent on LOL, I don't think we've had anyone post from your part of the world so it's nice to see you here.

Also, once you've been here as long as I have, you see the same old, same old subjects coming up time and again.

When somebody comes up with something thought provoking like this question of your's, then that is when this Forum gets really interesting.

Logically, because Clowns are shoaling fish and highly socially structured it is very likely that they give off chemical signals. Much of tight schooling fish behaviour, the way they move as a unified body, is based on subtle chemical signalling.

A book that i can highly recommend is "Fish Behaviour In The Aquarium and in the Wild" by Stephan Reebs ISBN# N-0-8014-8772-2 Comstock Publishing Associates, a division of Cornell University Press.

Certainly in nature, bright colouration such as a Clown's bright dress is often indicitave of some chemical defense. Obviously Clowns have been given their own Family Chromobotia recently as a recognition of their substantially different markings and colouration compared to other "Botia".

The yellow(ish) with black striping design is generally a "Hey look at me, I'm poisonous" warning sign. It's certainly not cryptic in nature. I wonder though if en-mass, a shoal of clowns is visually confusing to a predator? That could be the key. Look at Tiger Barbs for instance...virtually the same patterns and colours......not poisonous though as far as I'm aware.

So that might be a factor to consider. Clowns don't smell bad from what I've detected during netting them, however chemical signals are usually far too subtle for a human to detect. Only comment I can make is that my wife had a Clown die years ago and go unbdetected for a while. When it was discovered, it stunk like no other dead fish she had ever experienced before or since and was incredibly slimey as well. Possibly, that might have been due to some decomposing chemical that other fish don't have? Just thoughts and ideas....possibilities.

I think that your question will generate a lot of debate. I hope so. LOL is at it's best when we get in a huddle and bash brains. :lol:

Once again, thanks for bringing up something of such interest. We love people here who think outside the box.

Martin.
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andyroo
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Post by andyroo » Wed Jan 11, 2006 11:34 am

JD,

Thanks for the response. The spine was my first thought as well, with the colouration denoting this.
But i never saw any wounds... even so trivial as a ripped fin... on the loaches to indicate an initial "tasting" attack.
Other loaches have the spine but no bold colouring. How do other loach spp do in predator tanks or in the presence of large/aggressive tankmates?

Andyroo
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Emma Turner
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Post by Emma Turner » Wed Jan 11, 2006 1:31 pm

Hey Andyroo, nice to see you at Loaches Online. :D
That is a very interesting question that you have posed, and something which I have thought about a lot. I have quite a bit of experience in keeping Clowns, and through the years, have had to move house with mine numerous times. Once, when I was moving a short distance away (about 12 miles), I bagged the Clowns and other occupants of the tank in mixed bags. That is to say some Clowns were in with Corydoras, some with different tetra species, some with Ancistrus, some with kribs, some with L number plecs, and so on, and then there were also some bags with just Clowns together on their own, and some bags with catfish/tetras etc etc (no loaches). When I got to my new location, the bags that contained just the tetras, catfish etc were fine, as were the Clown loaches on their own. However, in all other mixed bags containing Clown loaches, all the fish except the Clowns were dead or dying. The Clowns were all relatively small at that time, from about 3-5" I would guess, and all seemed in perfect health. There was a kind of mucus substance in some of the bags, which I believe was given off as a stress reaction. I also found this substance last year when we re-homed two large 10.5 and 11.5" Clowns - it was quite visible floating in the polystyrene box we had transported them in. I work in the aquatics trade and would like to think that I can catch/handle fish with minimal stress and I felt I would have made the journey as comfortable as possible for them. Since the first incident, I have always advised any Clown owners who mention that they are moving them, that they bag them separately to other species. I therefore feel that they are capable of giving off some moderately toxic substance that they themselves are immune to.
Hope this is of interest.

Emma
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DRLashambe
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Post by DRLashambe » Thu Jan 12, 2006 2:12 pm

I do seem to recall from my evolution classes that stripes do denote poison or danger, but that many creatures have similar colouring to trick predators into believing that they are dangerous.

I certainly think that their colouration makes them hard to differentiate, I recently found a clown with a "dot" instead of a middle stripe, and trying to pick him out from his tankmates to buy him was near impossible.

I did have a clown killed by other fish when my clowns were quite small. When I first got my tank up and running, a foolish person told me that freshwater puffers were community fish...the results were quite awful, and definately involved the puffers eating my clown.

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chefkeith
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Post by chefkeith » Thu Jan 12, 2006 4:10 pm

I agree that this is a interesting question. It's something I've never though of. In the wild, I imagine that clowns do have enemies like other large predatory fish, croc's, large birds, turtles, and such where a chemical defense would come in handy. I also know that Clown Loaches are considered a food fish for people of the Borneo/Sumatra regions. I wonder if anybody has gotten sick or has died from eating a clown loach?

I'll ask some cichlids keepers about this and see if they have anything to add.

I do wish that clowns had a chemical defense to ward off ich though.

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Erik
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Post by Erik » Thu Jan 12, 2006 8:48 pm

Hi Martin
Zebras have a striped pattern so that is diffcult for predators (lions) to attack. Maybe clowns are coloured that way for the same reasons?
Erik:)


Martin Thoene wrote:Hi andyroo, and a big welcome to Loaches Online :)

In all the time I've spent on LOL, I don't think we've had anyone post from your part of the world so it's nice to see you here.

Also, once you've been here as long as I have, you see the same old, same old subjects coming up time and again.

When somebody comes up with something thought provoking like this question of your's, then that is when this Forum gets really interesting.

Logically, because Clowns are shoaling fish and highly socially structured it is very likely that they give off chemical signals. Much of tight schooling fish behaviour, the way they move as a unified body, is based on subtle chemical signalling.

A book that i can highly recommend is "Fish Behaviour In The Aquarium and in the Wild" by Stephan Reebs ISBN# N-0-8014-8772-2 Comstock Publishing Associates, a division of Cornell University Press.

Certainly in nature, bright colouration such as a Clown's bright dress is often indicitave of some chemical defense. Obviously Clowns have been given their own Family Chromobotia recently as a recognition of their substantially different markings and colouration compared to other "Botia".

The yellow(ish) with black striping design is generally a "Hey look at me, I'm poisonous" warning sign. It's certainly not cryptic in nature. I wonder though if en-mass, a shoal of clowns is visually confusing to a predator? That could be the key. Look at Tiger Barbs for instance...virtually the same patterns and colours......not poisonous though as far as I'm aware.

So that might be a factor to consider. Clowns don't smell bad from what I've detected during netting them, however chemical signals are usually far too subtle for a human to detect. Only comment I can make is that my wife had a Clown die years ago and go unbdetected for a while. When it was discovered, it stunk like no other dead fish she had ever experienced before or since and was incredibly slimey as well. Possibly, that might have been due to some decomposing chemical that other fish don't have? Just thoughts and ideas....possibilities.

I think that your question will generate a lot of debate. I hope so. LOL is at it's best when we get in a huddle and bash brains. :lol:

Once again, thanks for bringing up something of such interest. We love people here who think outside the box.

Martin.
16G bent corner planted ,pressurized Co2, turbotwist 9w, jebo 828 , 36 led

crazy
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Post by crazy » Thu Jan 12, 2006 10:14 pm

I've also had mucus floating when we moved the clowns, and when two small clowns were in the (heated) goldfish tank they were the only fish the gold fish didn't try to eat, but they did try to eat the Fire Belly Newts that were also in there temporaily, and they do have posion glands.
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Post by ashdavid » Fri Jan 13, 2006 8:26 pm

How ya doing everyone? I was asked someone on this site to share my experiences with large predatory fish a clown loaches.

Well where to start? This topic is very interesting indeed, I have never heard of clown loaches having this kind of defence mechanism, although completely plausible. I know they have some nasty spines on them that stop preds from eating them.

I have kept clowns with many big preds before and have quite a few stories with different outcomes. My first one was with a big dovii and a clown loach about 6". The dovii attacked the clown loach and tried to swallow it tail first, but could not, he then spat out the repeatedly tring to swallow it head first and tail first. This went on for about 12 hours before he gave up, the loach lived. I also have a jaguar cichlid that attacked a 4" loach ,but this time the jag was victorious, all that was left of the loach was a fat belly on the jag. This jag has eaten many small loaches after that. The dovii has also eaten 2 small 2" loaches since his experience with the 9" loach.

I have a nile perch swallow a 9" clown loach in one gulp, no signs of distatse or discomfort ect, it was gone in about 20 secs after putting it in the tank. This perch has not tried to eat a clown loach there after ,but I will say at that time I was tring to get him to eat prepared foods rather than feeders, he now shows little intrest in feeders which could be one of the reasons why he has not taken a clown loach since then.

Anyway what I am tring to say is that if there was a chemical defence going on here, these fish are not affected by it. It may be that it only works on certain fish, I don't know? But this is what I have experienced.

Cheers. :)

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chefkeith
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Post by chefkeith » Sat Jan 14, 2006 1:54 am

Wow ashdavid. I'm a little shocked. I was hoping that your clown loaches had put up a better fight and had not been eaten.

One thing that you didn't mention, but I will, is that you have some awesome tanks, one which is close to 2000 gallons.

Thanks for sharing your experiences. After reading your post, I highly doubt that clowns have any chemical defences.

andyroo
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Post by andyroo » Sat Jan 14, 2006 12:01 pm

Chiefkeith,

Based on the responses above i would have to disagree....

1-Colours point strongly to a defence, possibly a chemical one (as well as the spine)
2-Transport bags containing film that kills everything but the loaches points strongly to a chemical defence, likely toxic rather then just distateful and brought on by stress.
3-Locals eating them in Borneo: the mucus containing the toxin may be either wiped clean from the fish in the preparation process (as is done here with soapfish) or it breaks down in cooking. Ask the fisherman. They will tell you.
4-Goldfish, loaches and fire newts: I donno... could be a different toxin, or that the newts produce the toxin mainly in glands behind the head... so nibbles on the tail won't taste so bad(?) Newt toxin may also dilute quickly in water (semi-terrestrial animal) rather then being bound in a skin slime. It's fairly tough to get a toad to emit poison... you have to beat them up pretty badly... not that i'd know....;)
5-BIG fish predation. Sorry for being a bit of a neophyte, but i don't know what a dovii is... nasty no doubt. Cichlid? A gulper or more of a biter? I work in corals here, and what i've seen in fish predation on fireworm polichaetes (a major coral predator: they have nasty irritating defensive spines/hairs) is that if a fish can swallow it hole it will, but if it can't it won't even try. I reckon we're looking at something similar. The dovii couldn't swallow it... though it kept on trying, which kind of screws up my theory... maybe they're immune or a little dim... so eventually gave up with little (survivable) damage to the clown. But the jaguar and the perch did gulp it down in a single go... past the lips or taste buds or smell receptors which may have warded off disaster.
Very interesting that the perch has never eaten another clown and isn't so big on live food/feeders anymore. He may have learned something (?) Also of note is that this perch victim had only just been put into the tank. Defences take energy, so a loach not feeling stressed may not produce the toxins right away, thus the perch didn't feel it until afterwards, or not at all. How long were the loaches and jags/dovii together prior to consumption? With the puffers... i don't know, but that in nature puffers eat some nasty smelling and likely chemically acitve stuff like sponges, tunicates and whatever else they can catch and crunch up.

A few interesting experiments for anybody working in a lab situation might be 1) to check the skin/slime for chemicals/toxins and 2) to compare growth rates for loaches in docile versus more aggressive tanks communities. (toxin production takes energy: should slow growth)... Nice, publishable stuff.

Animals, that are not heavily preyed upon for one reason or another (top of food-chain, chemical defence, few predators in area, large size) will often have a reproductive pattern related to this... slow growth, late reproductive maturity, few offspring, long lifespan.... these loaches seem to fall into this group.

This would explain why my loaches never grow. Too much invested in chemo-defence. Must stick with kinder tank-mates....

however, having said all that, it's not unlikely that the striped patterns and schooling behaviours work together as well. As several of you have pointed out, a moving school turns into a swirling mass of yellow and black.

Martin, you're right... these discussions are fun.

Damn... i'll need to change my thesis topic again...

Please excuse my spelling. Wife's birthday party last night. Hung-over all to ras.

Sorry for writing so much in a single go. I know it's less user friendy to read.


Andyroo

PS: Ashdavid... I hear you run a 2000gal set-up.... i've been hired to create a large, idiot-proof marine tank for a hotel. Any suggestions or contacts? I did this kind of work in Uni in Vancouver, but it's a different ballgame now...
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Emma Turner
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Post by Emma Turner » Sat Jan 14, 2006 3:37 pm

As mentioned earlier, we have seen that Clown Loaches are capable of producing quite a bit of mucus. This could be primarily used to aid the fishes immunity to pathogens. As they are termed 'scale-less', it is possible that they have a higher capability to produce mucus to compensate for less protection against parasites in the form of scales.

Andyroo - when your arrowana went to go for your Clown, there is surely a real possibility that it sensed or tasted this mucus and backed off. However, in the case of a large predatory fish gulping down a smaller loach in one go, it may not suffer any ill-effects due to their particular method of eating and digestive process (i.e acids in stomach de-naturing proteins within the mucus).

Personally, we do not believe that the primary reason for the suborbital spines seen in Botia is for defense against predators. Through years and years of observing what could be termed as a relatively large social group of these fish, it would seem that they are most regularly used in territorial disputes among themselves.

It does make sense that the patterning and shoaling of these fish is one form of defence, especially when the fish are smaller. In lower light levels, which these fish prefer, the effect may be even more pronounced.

Here are some photographs which show the 2 large Clowns we acquired last year. At the time, I didn't post these particular shots as I felt the floating mucus may have affected the quality of the photos. This is the same stuff that was floating in the bags when I moved those other smaller Clowns several years ago:

some mucus can be seen here floating above the lower fish's pectoral fin:
Image

again, it can be seen floating above the pectoral fin and above the head of the other fish:
Image

and here's a closer shot of the floating mucus:
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Post by andyroo » Sat Jan 14, 2006 5:08 pm

Emma,

I see these snaps and it breaks my heart that i can't get my clowns to grow... I suppose we're illuminating some possiblities as to why. I've got six fish all under 8cm in 100 gallons with high flow.
Fantastic set of fish by the way.... What, 25-30cm long?

Re; predation with biting versus complete swallowing... that's exactly what i was getting at. The linings of the throat and stomach may be less sensitive to these irritants/toxins/dramas or stomach acids destroy them.

I've seen mucus like this pictured on koi, minnows and trout and all sorts of other stuff under unhappy, hot, skunky or turbid conditions... though the conditions pictured don't seem bad at all... and i wouldn't expenct them to be.
Have you found it to be different to discharges of other species and/or specific to these guys? You've got much more and wider experience then i. My little loach gets trails of it (mucus) off the pectorals when he's digging for snails as (i guess) a reaction to sediment/sand accumulation on fins/skin... and possibly potential pathogens or irritation. Mucus may provide a protective layer usually provided by scales... cool.

I don't know nearly enough about fish physiology to comment much beyond this... sorry.


Andyroo
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chefkeith
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Post by chefkeith » Sat Jan 14, 2006 8:33 pm

I just started a thread at Monsterfishkeepers.com about this topic. Quite a few people there keep clown loaches with predator fish.

The thread can be found here-
http://www.monsterfishkeepers.com/forum ... hp?t=14059

edited-
I think you all might be on to something. I remember an episode of the Simpsons where Homer got high by licking a toxic frog or toad. Perhaps one of us should try licking a clown loach.

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