Will two canister filters affect any fish stocking levels?

[dark_spell]

Let's say you have a 55 or a 75 gallon tank with two canister filters. Does that mean you can put more discus/fish instead of just having one filter? Would you still follow the 1 discus per 10 gallon rule?

[Kingfisher]

Let's say you have a 55 or a 75 gallon tank with two canister filters. Does that mean you can put more discus/fish instead of just having one filter? Would you still follow the 1 discus per 10 gallon rule?

I would just stick with the 1 discus/10 gallon rule. The fish need the space to feel comfortable. Plus I think they secret a hormone that affect nearby fish. Cannister filters are also a closed system and will be competing for oxygen with your fish. Trust me, there are no short cuts with Discus fish. If you wanna enjoy your fish, then just stick to the rules and suggestions from this forum. Otherwise, you will be finding yourself playing doctor to your fish.

[fredoman]

Well, it'll add to the overall volume of the tank's water, the same way a sump or wet/dry does so I suppose so. What I'm sure you'll hear from the folks here is to err on the side of caution, and I would agree. I had a 75g with multiple filtration systems that I overstocked and it got pretty nasty.

I suppose the final answer would also depend on how often you intend to do water changes. If you're doing 100% wc every day or two, you it gives you a little more freedom.

[mmorris]

What happens if the power goes out?

[DonMD]

The only way I've heard that more discus can be successfully kept in a tank too small is with massive and frequent water changes. The only think the canister filter does is remove ammonia and nitrites.

Overcrowding your fish will increase stress, which can increase the opportunity for pathogens to make your fish sick. I'd advise against it.

[fishorama]

I like 2 filters so I can really clean 1 & not knock back the beneficial bacteria too much. The bacteria only grow enough to support the bioload, "extra" will die off. I don't think it allows very much higher stocking except for possibly boosting the gas exchange for better oxygenation, depending on the water movement created, discus don't like too much current. Greater surface area of the tank + greater surface water movement = higher oxygen levels.

Better mechanical filtration too but with my discus I use prefilters & frequent vacuuming so less stuff is sucked in anyway.

Discus are large fish that need swimming space too, 10g seems like a reasonable guideline with a bigger surface area better than a taller tank with less, they don't stack well LOL. Lots of plants or wood takes up space too.

[mjs020294]

Let's say you have a 55 or a 75 gallon tank with two canister filters. Does that mean you can put more discus/fish instead of just having one filter? Would you still follow the 1 discus per 10 gallon rule?

I wouldn't exceed the 1 Discus per 9/10 gallon rule but extra filtration will allow you to add a few extra smaller fish.