Loaches Online Forum

Hi everyone, I have a 120L tank that has been set up for at least 6 month now.
Originally we had 5 Neon Terta, 4 Glass Bloodfin Tetra, 2 Clown Loach, 1 Bristle Nose and one Hillstream Loach.
We moved house and all the fish with it roughly 2 months ago and all the fish seemed to be doing ok. Recently I bought a brown Mystery snail which has taken well to the tank, laying a clutch of eggs a week later.
Now last week I notice one of my Clown Loaches was lying on its side at the bottom of the tank. I quickly did some research and found that this could just be one of the behavours of clowns. But after another couple of days of sitting at the bottom it dissappeared, I assume dead and eaten by the rest of the fish.
The other Loach seemed rather depressed while the first was on his way out. Often swimming back to check on him. When the first one eventually went I decided to purchase another friend for him as he didn't seem as active when he was alone.
We now have two new clowns and at the same time I bought three Kuhli Loaches. These must have had some problems in the pet store as one died almost an hour after introduction and another died the next day. The third still seems ok, for now.

Now it seems that the second of the original clowns is having the same issue as the first. Lying down for a couple of days and I couldn't find it this morning.
The two new Clowns seem fine.

I had the water tested at the pet store and they told me that everything was normal. Ever so slight amount of phosphorus in the water and sold me something to take care of that.
At the same time as purchasing the snail I bought some Algaefix and a water clarifier. Could these have caused the problem with my Clowns?

Sorry for the wall of text.

Some more info: The rest of the fish seem to be doing fine.
Since not long after I set up the tank, I've had a cloudy water problem, hence the water clarifier I bought. Could this be an issue?

Update: Second Clown is indeed dead as well as one of the Neons. I'm kind of at a loss as to what to do. Any suggestions?

What size is the tank? Does your '120L' mean 120 liters or 120 gallon, long?
What temperature are you keeping this tank? You have fish that thrive best at temperatures all over the scale. Should not keep these fish together. Research each species you have now, and see what it would take to fix the existing problems: More tanks so you can keep fish that have different needs? Or return some fish and just keep the ones you can care for.
Hearing a store say, "Your water tests just fine" is SO bad. Get the numbers:
Ammonia
Nitrite
Nitrate
GH
KH
pH
Each of these tests will tell you something about the water, and just hearing 'It is OK' does not mean anything. OK for what?
The store was concerned about phosphates? That is really odd. Unless they are crazy high, that is a non-issue.

Some algae control products can have a bad effect on the fish, but I cannot say that is what killed the Clown Loaches. How soon after using this product did the problem start?

Water clarifier does not usually cause problems. It is not usually needed, most cloudy water issues go away by them selves, or with just a few extra water changes.

Until you figure this out, I would suggest more frequent, perhaps larger water changes. If there is something not right in the water, dilute it, start getting rid of it. Clean the filter and put new activated carbon in the filter, then change it out in a few days for some fresh AC.

Your water parameters were probably off. Never get your water tested by the pet store. They will always say that it is okay. What you should do is purchase an API liquid test kit to test your tank water. Clown loaches are very sensitive to changing water conditions. There could have been toxins in the water when you put other fish in. Always quarantine your new fish for a few weeks before adding them to the main tank, if possible. Get an API liquid test kit from the pet store and test your water. Ammmonia and Nitrite should be 0ppm, you should have some nitrate, and the pH should be acidic, which means under 7, but no higher that 7.5 for the clown loaches.

Never trust your lfs if their summary is "Ok". For $42 + $7.50 You can buy a master test kit from Age of Aquariums but you can get the same product, delivered, for $42 on Ebay. So do a liitle shopping round. A PH balance kit is essential IMHO - especially with loachs. I only use the mater kit every couple of months. I'd suggest regular water changes but I don't know what you're using to dechlorinate, change temp ... to put in you tank.
Please stop buying loachs until you've got the water issue sorted out?