Are Lights Necessary?

[Kasey Grohowski]

Are lights required in a FOWLR tank, more specifically a predatory tank (Marbled Catshark, grouper)? No live plants. Will lights encourage more beneficial bacteria growth?

 

[ReefGeezer]

It would really depend on the "Live Rock". Some of the life on it may need more light than would be available from a regular fixture. However, if you only care about the "beneficial bacteria" then any light will do.

 

[Kasey Grohowski]

It would really depend on the "Live Rock". Some of the life on it may need more light than would be available from a regular fixture. However, if you only care about the "beneficial bacteria" then any light will do.

I started with dry rock

 

[bluprntguy]

a light isn't required for a fowlr beyond what you would install to be able to see the fish.

 

[Kasey Grohowski]

a light isn't required for a fowlr beyond what you would install to be able to see the fish.

So just a moon light should be fine? My shark doesn't really like the brighter lights.

 

[bluprntguy]

So just a moon light should be fine? My shark doesn't really like the brighter lights.

Most moonlights are going to be all blue. It seems like a low powered LED light that is dimmable/controllable would be a better option and allow you to gradually adjust the lighting until the shark is more comfortable. Maybe a couple Kessil A80's?

 

[lion king]

Not at all, I have lights on my predator fowlrs just for my viewing pleasure. I keep one nps coral tank that only have a few low level leds. I even suggest to people keeping the lights low will manage algae growth. You will get cryptic sponge growth and other beneficial growth without lights. Both the fish you mentioned will likely be much more active in low to very low light, even ambient room light my be enough to enjoy.