Can lights be too bright? Anything I can do to dim them?

[swifty]

I have a T5NO Aqueon strip for my 4 foot tank. It is a 3 foot strip, so depending on where I place it, it covers only 3/4 of the tank. The other day I moved it to the extreme left side of my tank, and have noticed all of my fish (silver dollars, JD, convict, firemouth) have moved to the right side, out of the direct light and generally spend most of their time there. Anytime they go on from the timer everyone scatters and huddle in corners for 5-10 minutes before retreating to the right side.

If I place it in the center, they just go to the left/right sides.

I have a spare T8 fixture, but it is only 30", so it has a 24" bulb. Anyone with an experience like this? Are my lights too bright, or will they adjust to them over time?

[swifty]

Ok well, looks like they really can be too bright.

I put that T8 fixture on to experiment, and after 15 or so minutes of them hiding, they're all out in the open. Swimming back and forth, across the tank, cruising around. Looks like I'll have to find a T8 that can fit the entire tank now.

[Delapool]

I found they adjust after a while but do appreciate shaded areas to hang around in. I have some fairly bright led light boxes and find the fish have got used to them.

[wildroseofky]

You could add some floating plants to give them some cover if you want to use the T5 light. My neons stay near the bottom when my lights are on. I have some driftwood shaped like trees with moss on them for then to swim around under. They will get used to the light if you just give them time.

[BBradbury]

Hello swift...

Hornwort, Common water weed (Anacharis) and Pennywort are good shade plants. Just drop some individual stems into the tank, no planting is needed. The filtered light under this plants is perfect shade for your fish.

There is always the more creative approach to shading an area of the tank. Emerse the root ball of the Chinese evergreen. No better shade, but this land plant is pretty large. I keep them in my 55 gallon tanks.

B

[Fishfur]

Frogbit would be ideal for this, as would floating water sprite. Both provide good shade, their roots offer feeding and hiding places and the plants themselves are great nitrate suckers and attractive.

Water sprite produces plantlets in almost every notch of every leaf, so you can toss out those that grow too large and let the small ones grow out. Frogbit produces runners that sprout plantlets, but they're easily controlled. Both plants are capable of completely shading out the light if allowed to grow unchecked, but because they're large, controlling them is easy. You could likely sell extra plants easily enough.

[swifty]

Plants were out of the question as I have silver dollars.

I ended up going back to the T5NO fixture, but increased the silver dollar school size from 3 to 5 and it seems to have calmed everyone down. The silver dollars aren't huddle in a corner anymore, rather are roaming the tank which is bringing the cichlids out of hiding.

Thanks for the ideas