Does sump volume count towards number of fish?

[Discusdude7]

Ordered a 90 gallon tank. Will have a sump underneath (30-40 gallons). My question is that will the added volume of the water from the sump count towards the number of discus I can have in that tank? By the "10 gallon per discus" rule I can have 9 discus in the tank but can I get 3 more if I have a 30 gallon sump? I will still be doing daily/ every other day water changes.

[trungnguyen]

that's a good question. I have been wondering the same question like that. I have 100 gallons tank with 30 gallons sump...let's wait for experts answer that for us.
Thanks for bring it up.

[pastry]

YES

[Wes]

Up to a point. 13 adult discus in a 30 gallon tank with a 100 gallon sump so still a 130 gallons. That would only work with sardines

[dkeef]

Sure does.

[dr.nick73]

I would say yes but before you add the extra fish just make sure the display tank is big enough… for example if you have a 90g tank with 75g sump you could put 12 4-6" discus and be ok but if you had a 75g tank with a 90g sump having 12 discus in the 75 would not work…. always go as big as you can on the display tank

[Discusdude7]

So if I have a 90 gallon tank with a 75 gallon sump I can have 16 fish?

[Wes]

So if I have a 90 gallon tank with a 75 gallon sump I can have 16 fish?

sardines

[banks2]

What about a 75 gallon with 30 gallon sump ??
Thanks Dave

[OC Discus]

Maybe there is a square inch rule along with the gallon rule. Does anybody have one?

So if I have a 90 gallon tank with a 75 gallon sump I can have 16 fish?

[lipadj46]

So if I have a 90 gallon tank with a 75 gallon sump I can have 16 fish?

I would say that is way too many.

What about a 75 gallon with 30 gallon sump ??
Thanks Dave

I have 10 adults in a 75 and the are pretty packed in.

[DiscusLoverJeff]

I would think if you have an empty tank, meaning just fish and BB it would be fine to add the sump to your calculations for how many will go into a 90 for example. Now if you have a planted display tank for example I would stick with the tank only rule and max out at 9 or 10.

Remember that with all the other things in the tank it is taking up volume and it limits your space.

[Cichlidcraze]

I would say yes and no. Although the sump will allow for the extra bio-load, fish still need space to swim and sometimes escape the dominant fish. Very difficult when they are packed in like sardines. I would look at a sump more as a buffer to help maintain better water quality.

[Magoo40]

Just confirming that the sump would also be counted in any water / med treatments based on tank voulme ...yeah.

[Discusdude7]

Just confirming that the sump would also be counted in any water / med treatments based on tank voulme ...yeah.

Thanks. I didn't even think about that.