# Fish hide/sink to bottom when light is on



## mrrobinson88 (Nov 6, 2012)

I have 8 Tropical Fish (2 Tetras, 2 Zebra Danios, 3 Silver-Tips & 1 Plec).

I have had the tank set up for over a month now and have completed a course of nitrate and ammonia remove, plus chlorine remover. The tank is set at 26 Degrees. The fish are healthy.

The only problem I have, is that all fish (except the plec) seem to act strange (hiding/sinking to the bottom, sometimes erratic) every time the tank light is switched on. It seems quite strange, seeing as they have only been acting this way over the last 7-10 days.

When the tank light is switched off; immediately they are swimming around as normal, covering all areas of the tank.

Any suggestions??l


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## twocents (Feb 22, 2010)

too bright??


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## Geomancer (Aug 23, 2010)

Going from dark to high noon in a split second is scary for them.

Likely you don't have enough cover in the tank, most fish come from forests so they are under trees and not out in the open in direct sun.

You also have too few of some fish, schooling fish should be in numbers of 6 minimum, anything less and they'll be stressed.

What size tank, and what kind of pleco? I assume you mean Silver Tipped Shark, do you know the actual species name? If it's the one I'm thinking it gets very large at 14"...


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## dieseldoc (Feb 2, 2010)

From what I have experianced and have read it takes approximately 30 minutes for the fishes eyes to adjust to the light. With the light being turned on it startles and stresses the fish so the dive to the bottom. The same goes as well when the light is turned off. If they go to the bottom and stay there I would say as well as others have said the light is to bright for them. By bright I am not refering to the wattage but the kelvin rating of the bulb. The bulb may or may not have this rating printed on it. Approximately 6500k is equivelent to day light. This to may be to bright as well with out some floating plants to shade them. Another thing that I have found with my tank of tetras is that if there is a light turned on in the room (Not the tank light) prior to turning on the tank light this will help them to not be startled when the tank light comes on. The same goes with turning the light off. Turn the room light on before turning the tank light off. I turn the room light on in my fish room about half an hour before the tank light turns off and then leave it on for about a half hour after the tank light turns off. Hope this helps.


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## mrrobinson88 (Nov 6, 2012)

Thanks for your replies. I'll be sure to add some more of the same species of fish already in the tank, and turn the light on/off with my room light on (at least) half hour before/after doing so.If the problem still persists, I'll look into getting a dimmer light


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## Byron (Mar 7, 2009)

I concur with what other members have suggested, and would also add that floating plants are a major benefit to forest fish. Not to mention their other benefit of improving water quality.


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