Small schooling fish

Question

Hello, I have trouble with adding fish with my 10 gallon tank. I have 4 corys for quite a while. I recently got 5 cardinal tetras. They are gradually dying 1 by one. When they die, I always find them below under the driftwood. I think they are dying because they got scraped by the driftwood. I got 2 remaining. Why are they dying? What kind of small schooling fish can I add to my calm, planted tank?

And how do I keep otos alive? They keep dying the day I bought them. I had a few before, they died mysteriously after being in the tank for a few months.

Answer 1

Generally what you want is about an inch of fish for every gallon of water.

So, you're a little overcrowded in there... which could be a problem.

I realize it looks very empty... but when the fish reach full size the water will become dirty faster with more in there.

Also if you added 5 cardinal tetras at one time, your ammonia level in your tank may have spiked.  It's best to add fish in small doses in order to keep the ammonia level down.

You should either take a sample of your water to a pet store to have it tested, or buy test strips/drops to test the water yourself.

Otos are algae eating fish.. so if you run out of (or have too little) algae in your tank, they will starve to death.  It's best to supplement them with either algae wafers, or even zuchini.

Answer 2

get a test kit and test the water

Answer 3

I would check the tank pH and hardness.

Cardinals and Otos are both Amazon fish and prefer soft water and lower pH. If you tap water is very hard it may be difficult to keep them alive. Corys seem to be more adaptable and hardy, so they survive.

Otos are quite fussy about their water conditions at the best of times. If your tank suits them, they are fine, but if the water is not right they are hard to keep alive.

If your water is hard then try some male guppies or platies, they can handle that water better.

This is only a theory, but some water testing may show up something.

Ian

Answer 4

How long has your tank been set up for?

Get yourself a test kit and test the ammonia, nitrites, and nitrate levels.  Ammonia and nitrite should be at 0 ppm, nitrates under 20 ppm.  If those first two are showing up, then that's most likely why your fish are dying.

If those test fine, well, it could be a number of things really.  They're probably dying then floating down under the driftwood though.  

Any symptoms before they die?

Cardinals are a bit hardier then the neons, but still a sensitive fish.  Ditto with the oto cats.  I've seen it written, when buying oto cats, buy a few, and count on a few of them dying within 24 hours.  If they make it past the 2 week mark, you're usuallly good to go with them.  They just are so sensitive.

Are you also making sure you slowly adjust the fish to your tank?  Float the bag in your tank for about 15 minutes, then slowly adding a bit of tank water to the bag-I usually take another 30-45 minutes for that, then net them out of the bag-don't ever dump the water back into your tank.  The reason behind doing all that, is to allow the fish to adjust to any temperature and ph differences.  Otherwise, they can go into shock, but usually they would die off within a 24 hour period if that was the case.

Another problem with otos, when they do survive, they tend to starve to death.  They can be hard to get to eat algae wafers and other supplemental foods, and the algae in the tank isn't enough for them.  If yours lasted awhile, then that may be what happened with them.  

Check your water quality, and make sure that's not the problem.  If it's not, then maybe try a different store, maybe they have a better fish breeder with healthy fish.