HELP!!!! Fish Blindness????

[cashedin]

I have recently upgraded my 75 gallon tank from 4X96W Compact Florescent bulbs to 2X250W metal halide bulbs (10K). Now my lionfish and sailfin tang seem to be running into everything! I'm not sure if it is due to the lighting or not, but that is the only thing that I can see that is a drastic change and that might have caused this. I don't see any signs of disease (i.g. Ich) or anything else... My ammonia and nitrate levels are normal. My lionfish has been acting this way for a week and a half now and still has not eaten anything, the sailfin just started acting weird. I have put my net in the tank and the fish will swim right into it as if it was not there. It is very disheartening. Please help!

 

[Navarre]

My Sohal tang has recently suffered from what sounds like exactly the same problem. It was acting fine and dandny then when it went into quarentine whilst the tank was being treated it refused to eat. When it was returned to the main tank it kept swimming into things and just didnt seem to act in the normal manner. It refused to eat (or so i thought0 but after trying all sorts of its favorite food i discovered that it could not actually see the food! I put algae on a clip in the tank and it wolfed it down. After doing some research i discovered that this is a symptom of poor diet. The fact that it had refused to eat for 5 weeks in the Quarentine tank means its dietary needs were not met and it lost its sight. I fed it daily since then and it seemed to be recovering. Howevr, the macro algae in teh tank released all its stored nutrients back into the system at the beginning of this week and the result was that i lost the Sohal and the Blueface Angel Whether the daily special diet would have brought a complete recovery of hte sohal i guess i will never know. It was definately on the mend though. If the fish are refusing to eat and after a period of time they seem blind then i would suggest that they are seriously lacking vitimins etc in their diet.

 

[fraservet]

Malnutrition - particularly hypovitaminosis A, is certainly a possibility. I generally wouldn't expect 2 fish with such different dietary requirements and feeding habits to develop blindness simultaneously though.

I don't think it's likely that the lighting is the cause either.

Have a good look at the eyes, are there any obvious abnormalities?
Particularly any exopthalmos (swollen, sticking out eyes), cloudiness, bubbles in the eye etc.

What other fish do you have in the tank?
What exactly are your parameters?

Other possible causes of blindness include

- gas bubble disease
- toxins
- bacterial infection
- pH increase
- virus
- parasite

Of these, you can hopefully rule out any external toxins. Some parasites will be obvious to the naked eye. A virus is probably unlikely.
Gas bubble disease is a real possibility, it often affects more than one fish.
Bacterial infection is again quite possible.
Did you have an algal bloom after putting the new lights in? This can raise the pH considerably and can cause blindness. Test your pH if you haven't already, but even if you have, and it's normal, this could still have been the cause.

My porcupine puffer also suffered from a bout of blindness of unknown cause. It recovered 100% within a couple of weeks, so there is some hope.