Reducing my stock without bloodshed

[mattybecks]

Hello.

So I have a 5ft (just under 500L) aquarium now. Which has been stocked with African fish for about 18months.

I got all the fish really small and they have grown up together, so I don't really have any problems with aggression.
As the fish get bigger I think they will be needing more space - is it possible to reduce the fish I have to only the Livingstonii (two males which sometimes have a tussle, but mostly one sticks to one side of the tank, and the other keeps his space on the opposite side - both have been fertilizing eggs with females, but they spit the eggs out after about a week) and the compressips (which never have a problem with anyone - also breeding but eggs don't make it very long) my two polys and the black catfish (who never fights with anyone).
I'm not sure if because the tank is well stocked the aggression is dispersed? Will removing the other fish then upset the balance? Maybe I could keep my two kenyi cichlids? and the giraffe cichlids too.

Or should I just leave everything as it is? I would love to have a species only tank one day (the livingstonii) I just grow to attached to my fish haha.

Filtration - I have one big biological filter that runs along the full length of the top of the tank, and two powerhead sponge filters in the tank (500L per hour and 2000L per hour)

 

[james99]

If its working I would leave it as is. Just remove anyone that is overly aggressive or that gets picked on too much.

 

[duanes]

If your concerns is partially about keeping fry, have you tried an egg tumbler?
After you notice a holding female, catch her in a net, she will often immediately spit the eggs in the net, and you put them in the tumbler hanging on the tank. The are available commercially, or you can make your own, I have had both. Sometimes they work, sometimes they don't.


The one above is commercial, the one below, I made from a specimen box.

 

[james99]

Also I would keep an eye on the catfish, which looks like an Asian upside down catfish. From what I've read the get big and mean.

 

[DJRansome]

I would not save fry until you have the species tank. I think you might be able to get away with 3 Livingstonii males and 9 Livingstonii females even though it is a 5 foot tank.

 

[mattybecks]

If your concerns is partially about keeping fry, have you tried an egg tumbler?
After you notice a holding female, catch her in a net, she will often immediately spit the eggs in the net, and you put them in the tumbler hanging on the tank. The are available commercially, or you can make your own, I have had both. Sometimes they work, sometimes they don't.


The one above is commercial, the one below, I made from a specimen box.

Thanks this looks great !

 

[mattybecks]

Also I would keep an eye on the catfish, which looks like an Asian upside down catfish. From what I've read the get big and mean.

oh geez. Ive just googled both and they look very similar. The Asian does seem more likely. African looks like it has rounded fins, where as mine has more Asian looking ones and fits the description exactly in terms of behavior. Do you think this will pose a problem for me in the future? There is a lot of conflicting information on their size too. Same say 7inch, others up to 12.

 

[james99]

I've never kept one, so I can't say how it will do in your tank. Maybe try the catfish section or look up the profile on planet catfish for size and aggression. The African upside down catfish is brown with black markings. There are 2 that are called upside down catfish in Africa. Synodontis nigervinter and eupterus. Nigervinter stays small, the other gets about 8". I have kept both eupterus would do best with larger cichlids.

https://www.planetcatfish.com/common/species.php?species_id=21

 

[paulW]

I would not save fry until you have the species tank. I think you might be able to get away with 3 Livingstonii males and 9 Livingstonii females even though it is a 5 foot tank.

YES , great advice.. In OP's tank, there is too much risk of hybridization.

 

[kewpiefishypewpie]

Hello.

So I have a 5ft (just under 500L) aquarium now. Which has been stocked with African fish for about 18months.

I got all the fish really small and they have grown up together, so I don't really have any problems with aggression.
As the fish get bigger I think they will be needing more space - is it possible to reduce the fish I have to only the Livingstonii (two males which sometimes have a tussle, but mostly one sticks to one side of the tank, and the other keeps his space on the opposite side - both have been fertilizing eggs with females, but they spit the eggs out after about a week) and the compressips (which never have a problem with anyone - also breeding but eggs don't make it very long) my two polys and the black catfish (who never fights with anyone).
I'm not sure if because the tank is well stocked the aggression is dispersed? Will removing the other fish then upset the balance? Maybe I could keep my two kenyi cichlids? and the giraffe cichlids too.

Or should I just leave everything as it is? I would love to have a species only tank one day (the livingstonii) I just grow to attached to my fish haha.

Filtration - I have one big biological filter that runs along the full length of the top of the tank, and two powerhead sponge filters in the tank (500L per hour and 2000L per hour)

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That's a cool mix you've got there, I've always been a fan of Livingstonii and Venustus.