withtim

I'v had two 5 inch silver sharks for about 4 weeks and recently I'v noticed that they have become much darker in colour and their dorsal fins have become alot flatter down to their bodies than before. They are also alot less lively than when I first got them. I maintain the tank sufficiently and do regualar 30% water changes once a week . Does anyone no what the problem may be?
cheers

capekate

Hello WithTim
Welcome to fishlore. Wanted to let you know that I moved your original thread from "Using the Forum". As that is for Forum issues and you should get more replies here in the specific category under Bela Sharks/Silver Shark forum.
Hope this helps!
As far as your fish darkening up and clamped fins, Its possible that it is just stressed. Since you say your water perimeters are fine, can you let us know what your readings are? How long your tank has been set up? And what other fish you have in the tank with the shark and how big is your tank?
thanks, ~ kate
EDIT: I just checked you did have your aquarium info available. sorry for the questions asked....