my sick corydoras trilineatus

Question
I have three corydoras who were originally in a 32 inch tank with a variety of other fish until they were being picked on by a newcomer in the form of dwarf chain loaches.  I then moved them into a smaller 28 litre tank with three panda corydoras and a siamese fighter.  Everything appeared to be fine although they did seem to be having problems with stability.  As the tank was too small I bought a 35 litre tank and moved them in being carefull to use the same water and filter.  I check the water regularly and readings for amonia are <0.6, no2 0, n03 <0.5, ph 7.5, water hardness 80, carbonate 80(slightly acidic.  Even so one of them appears to have developed a swim bladder infection,which I am trying to treat, and another is showing symptoms.  The third is fine at the moment but the two are very pale.  The rest of the fish are fine but my cherry shrimps have also been mysteriously dying.  Please can you give me any explanations as to what is happening and what I can do about it.  I am using Interpet Aquarium Treatment 13 Swimbladder treatment

Answer
Hi Mich

Well first, adding any type of fish medication to a tank with shrimp in it will kill them. Most fish medications contain copper which is toxic to invertebrates. Did you read the warning labels? I've said this many times on this forum and many have disagreed, but shrimp, snails and other such creatures do not belong in an aquarium with tropical fish. This is the primary reason why I say that.

Next, you really shouldn't move fish around from tank to tank like that. The stress and trauma will weaken their immune system and leave them vulnerable to all sorts of diseases and infections. When the Corys were being picked on by the newcomer Loaches, the Loaches should've been removed, not the Corys. Always check compatibility prior to buying new fish and adding them to your tank.

There really isn't much you can do for Swim Bladder Disease. Treat with a broad antibiotics like Maracyn, the Interpet you are using. Clean water is the rule for all diseases and infections. You may add 1tbsp of Aquarium Salt per 5 gallons of water. The salt will relieve their stress. Before adding any more medication to the tank, you need to get the remaining shrimp out of there.

Hope this helps, good luck!

Richard