How many BN's?

I might do 1 for the 20 gallon, 1-2 for the 36 gallon 3 for the 75 gallon but this is JMO

They will clean a tank in a hurry. Don't overstock them and be prepared to feed algae tabs or other suitable BN food.

I have 2 in my 55 with no issues and 4 in my 150. So, I think you could easily do 3 in your 75. I would try 2 in the 36, but if they end up both being males, it may be an issue..or maybe not. 1 in your 20.

If it is a 20 long, I would say you could do 2.

archer772 said:

I might do 1 for the 20 gallon, 1-2 for the 36 gallon 3 for the 75 gallon but this is JMO

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I agree, just make sure the two in the 36gal are male/female and the 3 in the 75 are 1 male/2 female

As long as they're small I'd say a few more temporarily until they get to 2+ inches but be prepared to separate the males. As you can sex them you may need to move some boys. an M & F pair in the 20 (long or tall?), 1 M & 1-2 F in the 36g, 2 M & 3 F in the 75g, But after they spawn... you'll need more tank space ...so not all of the possibilities if you want to grow fry up.

The concern with BN is the number of males in the tank space, that is assuming you supplement food to meet their dietary needs. The 20 gallon and 36 gallon could accommodate 1 male and numerous females. If you has many caves and hiding spots you could even try two males in your 36 gallon. The 75 could easily accommodate 2 males. For reference I had a 34 gallon tank with 1 males and 7 females. They spawned like mad, which created the need for a 10 gallon recuperation tank for the male

:iagree:The only thing I'll add is that for the 20G, unless you're going to breed them, I would only keep one in there. And that one will need to be fed with supplemental food just like any other fish. There won't be enough natural biofilm or soft algae to feed it. Same goes for the 36G....if you're not looking to breed them, just put 1 or 2 in at the most. If they both turn out to be males, they won't fight. It's when there's a female in the mix to compete for that the BN males will fight to the death. They would still need separate cover places and plants to break up the space between their cover spaces. I have 8 or 9 in a heavily planted 75G....it's their breeding tank. I have one mature male and one male approaching maturity in there. I'm keeping my eyes on the boys since the girls are going to spawn soon. I have two caves that are totally out of eye view of each other. If I even suspect that they are competing against each other for the same female....one male will come out of there. And I don't raise any of the fry in that tank. I have a separate growout tank for that.