fish sickness

Question
My albino corydoras has an eating disorder, atleast I think so. I got him a week ago and it hasn't eaten much. I saw its belly and it is basically gone. It has gone inward. I just really can't explain. It also gets stuck to the filter or gets caught on  the heaters electical wire and doesn't move. I think it's dying, could he be?

Answer
Hi Christian,
He could in fact have internal parasites. which typically shows up as symptoms such as listless behavior, extremely thin fish, and usually eventually a refusal of food. Stringy white droppings are also a sure sign.

But before we go any further its best if you first check all possible environmental causes. The most important is the water quality in terms of ammonia, nitrite and nitrate level. These levels should always be as follows- ammonia-0 nitrite-0 nitrate-20 or less. If ammonia or nitrite are present at all, that is not a good sign and could mean your tank hasn't cycled yet - http://www.firsttankguide.net/cycle.php
or the bacteria (biofilter) has been depleted or destroyed by either an over-cleaning of the filter, chemicals (other than water conditioner) added to the tank, or even a water chemistry (pH, ect..) change.

Its always best to try 30% water changes for several days. There's nothing better you can do for your fish than change their water often. Try to repeat these water changes to further help the poor cory's immune system.

Internal parasites can attack fast and can certainly kill. Often they can be difficult to treat since the required treatment medication has to be eaten by the fish or mixed with their favorite food. But many fish don't eat when they have internal parasites. I know I had a very sad-looking and sickly Dwarf Gourami whom has internal parasites and didn't around much, mainly stayed very still and lost all his color, he wouldn't eat much and had constantly stringy poo. I moved him into a hospital tank and started him on melafix, aquarium salt, daily 50% water changes, and tried a few times a day every day to coax him into eating the medication. I used frozen brine shrimp mainly to mix with the med. He would refuse it to no end and it was frustrating. But eventually he would start to nibble here and there and soon was taking the food (even pellets soaked in the medication) more enthusiastically everyday. I remember I had to treat him for almost a month or so. But now he is a happy fish building bubblenests!

Just a question-- have you tried offering your corydoras frozen foods like brine shrimp or bloodworms? Few fish can ever resist that. If he flat out refuses food, even frozen worms. Then all you can do is try your best and start him on a medicated food. The one known as "GEL-TEK" is what I use. Start the daily water changes regardless, it'll help keep him more comfortable.

It would be such a shame to loose him. I hope he gets better!
Karen~