Originally Posted by Termato
Do a Massive water change. If he is alive it will give him a better chance of living AND you will be able to see in there better.
Massive water changes to neglected tanks ,or tanks where water changes have been few and far between often cause more stress to fishes than a series of smaller more frequent changes for same negelcted tanks.
Fishes will try to adapt to enviornment they find themselves in, even poor condition's.
They do this through osmoregulation, as they try to adpat to metabolites and mineral content present in their enviornment.
Sudden large changes,,even for the better,, makes this more difficult for the fish = stress.
Bettter in neglected tanks, such as the one mentioned here,, to perform perhaps small daily, or every other day 25 % water change and work slowly up to large water changes to allow fishes to slowly adapt to changing enviornment.
With regular weekly water changes from the outset of tank set up,,large water changes cause no issues unless... water being used is much different than what is normally used each week which if regular changes are performed,, can't happen to any large degree, unless one is using chemicals,powder's potions in the tank.
With regular weekly water changes the water in the tank will be close to that of the souirce water and fishes will thank you for the fresh,clean ,water by remaining healthier than those fishes where maint,water changes are lacking.IME