Do I get Sewellia or Gastromyzon?/how many?/will they fight?

[LoverOfLoaches]

I am considering buying one, two, or maybe even three of either Sewellia lineolata or an unspecified Gastromyzon species. In your opinion, which have a better personality, and are more hardy?

One of the reasons I'm interested in them is because I think its so cute when they scuffle and try to "top" each other. And I read that these scuffles rarely result in harm to either; and lots of people put videos up on youtube and what-not, of them "play fighting"...but as cute as I think that is, I don't want it to be a constant territorial fight that stresses the fish out to live with another fish they always feel they have to fight with. Do your hillstream loaches do this, if so is it often, is it just between males (or is it also a part of mating), and do you find that although it isn't harmful it IS stressful to them? Or is it okay for me to get two males knowing they will do this, and it will never be a big deal for them to get in scuffles? Or, would you recommend just getting one (or getting either two females or a male and female) so that there isn't any stressful fighting? Would 3 males diffuse the situation more, or cause more fighting? What would you recommend the number and sexes I get be (mind you, I'm not able to get more than 3), so that the fish can be happy and healthy? (I know not to combine Sewellia and Gastromyzon because the Sewella is likely to gang up on the smaller Gastromyzon.)

Hehe, I know this is alot, but I really want to glean what I can from fellow loach owners. I have read up on all they need to do well in an aquarium, ie strong water current, high oxygen, colder water, smooth rocks to graze algae/microbes; the only thing I'm unsure of is how to KNOW if my tank is oxygenated enough. Right now I've got a 55 coldwater that has 2 HOB power filters on full flow; a Penguin 350 (for up to 70 gal) and a Tetra Whisper 30/60 (for up to 60 gal). Is that sufficient? I know adding a power head would be ideal for a unidirectional current for them; but does this really also ADD oxygen? Theorotically, it should only add oxygen if it breaks or disturbs the surface of the water right? (otherwise, its just MIXING high oxygen levels with low level spots so oxygen levels are even throughout.) IF my filters aren't oxygenating the water enough, then should I add more oxygen by putting the powerhead at the top of the surface and angling it so it disturbs the surface? (But then, wouldn't the loaches want their current down at the bottom where they chill out, instead of the top level of the water where they frequent less???)

Please help!!!

[Hokum]

My 2P, i've currently got 3 Sewellia lineolata and i also enjoy their little scuffles, but i also try and make enough stones and cover that they don't see each other too often. I currently have 3 females and i'm looking to get an extra male. I use a Ventri on both my internal filters which seems to keep them happy for the oxygen content.

[Noto]

Breaking the surface is not necessary. If there is enough current that you can see a swell or ripple at the surface, that is enough to greatly increase oxygenation. This is because in static water, only a very thin layer of water is in contact with the atmosphere, and it does not interact much with the lower water. It doesn't take much current to break up that thin layer and bring more of the total volume of water in contact with the atmosphere.

Of course, your power filters are probably already doing this. You can increase their effect by dropping the water level slightly.

You can also add a venturi or airline to the powerhead to inject air into the water column.

Keeping the water towards the cooler end of your fish's recommended temp range will also help. Cool water can hold more O2, and cool fish require less O2. Even a few degrees can make a difference.

[Jim Powers]

Over the years, we have learned that the temperature requirements of these fish are not as cool as thought for all species.
The Chinese hillstreams, as a rule, tend to come from cooler temps, while the Sewellia and Gastromyzons come from warmer temps. I would shoot for the mid 70's F ( around 24C).
Also, I keep Sewellia and Gastromyzon together and it is not necessarily a problem. If they are of similar size, the Gastros will hold their own. If there is plenty of room, smaller gastros will be able to find enough food and will should not be harassed.

[Diana]

Add up all the gallons per hour that the manufacturers claim for their pumps and filters. If this is around 20 times the tank volume (55 x 20 = 1100 gph) then there is most likely plenty of water movement for these fish. Best if the pumps and filters were set up to work with each other, to mostly flow in the same direction.
This does not have to be from one end to the other of the tank. It can be from the back to the front, the way most hang on back filters are set up.

Yes, a gentle ripple at the surface is usually enough to suggest that there is enough water circulation that the oxygen is well distributed through the tank. In a taller tank (2' deep) you might want to specifically aim a power head from top to bottom, or from bottom to top to enhance the circulation this way. I have Koralia power heads near the bottom in several tanks, aimed at an angle upward, and I can see the added ripples at the surface. In tanks under 2' the HOB filters usually do a decent job, but I have added the Koralias even in these tanks.
The venturi attachment usually works best if the power head is pretty close to the surface, so I would aim this power head down perhaps at an angle, if you want to use the venturi at all. I think you get more water movement for less electricity if you do not use it.