Fish to Control Fry Population

[lunar jetman]

I've found that livebearers tend to find their limits in a tank, and keep a steady population going. Give a lot of cover and some will survive.
Any larger fish will take fry, what were you thinking of adding? The hardness may become an issue, so if you can tell us that (dGH if possible) it will help with suggestions.

That’s the best approach. At some point nature will take over and there won’t be enough space for more fish. The fry will have nowhere to hide so will get picked off, simple as that. Then if you lose a few adults they’ll be more room for some fry to survive.

i think you’re putting too much thought into this rather than other more pressing factors, e.g. hardness. ?

[EmperorMoth]

Hello all,
Thank you for your replies, my water hardness rests at around 10dGH. As for the fish for the new tank, I was considering rainbowfish, such as a group of Melanotaenia praecox. I’ve never really understood why water hardness is so important, could some of you please shed some light on why it is so? Thanks

[Vale!]

Hello EM

Stephen addressed this in a thread called "Hard Water, Soft Water and Fish" which should be in the 'Science' board.

In summary : fish in the 'wrong' water have to expend a lot of their energy to keep the correct amount of water in their tissues. The more they have to do this, the more prone they may be to pathogens and certainly to inefficient metabolic processes. The result may be a shortened lifespan and/or vulnerability to disease. The tolerance for unsuitably hard water varies between species and between individuals of the same species. In general, 'softwater' fish find it less stressful being in hard water than the other way round.

There are more issues than that to do with water hardness, and Stephen has kindly allowed me to collaborate with him to bring some of them to you via an update to his thread. Soon ... honest!