Livebearer and predator tank.

[Daan281]

Thanks for the elaborate repsonses gents! duanes I am cycling the tank and thinking of doing something similar in the sump with guppy grass (and some leftover valisneria i need to give a space), I am now contemplating mangroves as well cause what you did is on another level of cool. (See attached pics the available space in sump at 50x40x30 cms roughly)

Also could I scale down the fish by means of selecting other species in order to achieve the same dynamic at a smaller scale? Poecilia reticulata and wild type blue acaras seem to have more adequate size for example… Any other suggestions of species combinations? I have quite neutral tap at 7.4ph 5gh and 8kh, also have a RO/DI unit if needed for SA species when some interesting combination’s native range requires so.

Cheers and many thanks,

Daan

 

[duanes]

Andinoacara always seem a good choice to me, being about half the adult size 10¨(25 cm) JD.
They also tend to be a lot easier on plants.

Although my Panamanian Andinoacara coeruleopunctatus, never cut the live bearers any slack, they easily polished off guppy size and even molly sized sized live bearers, in my 180 gal cichlid tank.


The wild caught molly above is a little over 2¨, and only lasts in the sump itself., not the main tank
The only size dithers, my Andinoacara ignore are Roeboides, and Astyanax tetras.


The Astyanax hit about 2.5¨(6+ cms), the Roeboides about 4¨
I do use a lot of Vallisneria as a submerged plant in my sump, and find along with the mangrove trees reduces nitrate significantly.

 

[jjohnwm]

We see a lot of different versions of this question posted on MFK. Back in my "Hmmm...what if...?" days I tried to create one of these "eco-system-in-a-thimble" tanks many times, and it just never seems to work. If the larger species is at all predatory...and almost all of them are to some extent...the smaller fish just gradually disappear until all are gone. You are talking about confining predator and prey together in a small, small area; no amount of greenery or other cover will allow for successful long-term cohabitation if the predators actually decide they want to eat their little buddies. The only way it ever seems to work as planned is if the large fish simply don't want to eat the little guys.

I've managed to enjoy that Nirvana-like state with only a couple of tanks; once with an African arowana (Heterotis) and again with an Osphronemus Giant Gourami. Both of those gentle giants completely ignored all other fish, large or small, of all other species except their own. And of course, you can sometimes make it work when the predator is very large, and the others very small; I'm talking big guys in the 2-foot range kept with guppies kind of thing. In a case like that, the large fish simply won't bother pursuing the tiny ones since it will burn more calories doing so that it will ever obtain from eating them. But that isn't the kind of tank you are describing, and it requires some other avenue of disposal for the ever-growing swarm of fry.

I recall when I kept a Lophiosilurus Jelly Cat in a 2-tank shared system with a large colony of livebearers. Occasionally one or a few fry would get swept up by the overflow and end up in the Jelly Cat's tank. They were usually about the size of one of its eyeballs...and Jellies have small eyes!...and the cat never deigned to pursue them or acknowledge their presence...until one of them would blunder too close to one of the Jelly's stubby barbels. SSSLUUURRRPPPP! Next contestant please!

Good luck with your attempt to recreate predator/prey dynamics in a bucket. Keep us updated. I wish you the best of luck, but have my doubts.