trying to understand fish

Question
i have a 4 to 5 inch oranda from head to tail, ive had it for 3 mths already. he sits for a long time at the bottom of the tank, he swims around for a while then goes back to the same spot. the water is fine, nitrites, nitrates, and ammonia are all good. he eats the food we give it just fine, but he is to still and i know that oranda are middle swimmers but this one is not doing it. he also sometimes looks like if the back part of the body floats. someone said it could be the swim bladder, but im not sure about that, do you think it might be something inside, should i give it antibiotic meds? could my fish be ok, and what can i do to make him better? can you please give me all possible answers? also is algea bad for the fish? and how can i get rid of it? it keeps coming back. thanks  

Answer
Hi Rene,
Fish with swimbladder have trouble maintaining their balance. Feeding shelled peas has proven to help swimbladder problems. Feed him peas for a few days and he should be a lot better. Try not to feed him flake food as this will expand in his abdomen and cause him even more dificulty in swimming.
Algae isnt usually bad for fish unless it is red which indicates a problem with water quality.

Hope this helps
Chloe.