Population in Community Tank

[IvanK]

Hi All,

I have reached the point to ask for this - how do you control the population of your community tank? Mine is now 4 months old (4 months after stocking). I would say I now have a few populations of new fish, and the tank starts feeling on the brim of being overly stocked. So, I am starting to think of how to deal with this. Can you let me know what you usually do? My tank is 240 litres, I have guppies, platties and molies.
All comments are welcome.

Cheers

Ivan

 

[seedoubleyou]

Most will say don’t buy live bearers that breed so prolifically haha

Remove some and try to rehome them.
You could then maybe add a larger community fish like an angelfish that may predate on the fry.

I’ve only ever kept all male guppies around 10 years ago so I can’t offer much more advice than that.

 

[hypnogogia]

Predators was the way I dealt with it. Free live food.

 

[PARAGUAY]

You can get lucky and a shop will take some back(for free usually) but the supply they get from wholesale these days makes it rare

 

[Tyko_N]

You could then maybe add a larger community fish like an angelfish that may predate on the fry.

Predators was the way I dealt with it. Free live food.

Not sure exactly what the laws regarding this looks like in the UK, but wouldn't it be considered using vertebrates as live food? I think you would be ok if you had an accidental spawning and the tankmates ate the fry, while deliberately introducing a fish knowing that it'll eat some of its tankmates sounds a bit shaky. From what I can find "Currently under the 1911 Act it is not illegal to feed a live vertebrate to another unless you cause it unnecessary suffering", so, would being chased around a tank by a much larger fish be considered unnecessary suffering? Catching and humanely euthanizing the fry before feeding them to other fish should be much safer legally-wise, although much harder on the fishkeeper.

 

[seedoubleyou]

I think your logic and morals may be a little backward there @Tyko_N

I think I’d much rather a predator was taking taking care of population control over just removing fish and killing them.

Hence I suggested removing some now to rehome and then introduce a fish like the angelfish that would easily pick off new fry.

Seems a more natural way of doing it to me 🤷‍♂️

 

[Guest]

I had a tank full of platies as a kid, they were the first tropical fish I kept. But I haven’t kept them since for the very reason mentioned. Personally, I’d do what I did back then, give them all away and keep something far less prolific.

 

[Tyko_N]

I think I’d much rather a predator was taking taking care of population control over just removing fish and killing them.

Absolutely agree with you, I would much prefer to do it that way too. I have been involved with some fish research though, and from the legal side it's often the complete opposite; you need a bunch of paperwork for simple stuff like taking a blood sample or tagging, while euthanasia is more straightforward and easier to get a permit for than anything that might cause some pain, and any injured fish should usually be quickly and humanely killed. I'm not saying the rules are ethical, but in research you have to follow them nonetheless.

 

[Simmo]

I have introduced angelfish to predate the eggs and fry of my Emperor tetras that are breeding (too) prolifically. My branch of Fishkeeper/Maidenhead will also take Emperors, so a two pronged approach. Personally I’ve no ethical issue with this, many fish eat their own eggs and fry anyway!

Your tank looks good by the way, great plants! 👍