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.

 

[Chet E.]

I once tried an Umbra limi in with a JD. I've no idea how it fit that fish down it's throat, but it did.
.
I found Amatitlania myrnae effectively consumed young Limia perugiae. An occasional juvenile would survive, however without some intervention not enough would make it to sustain a population in a heavily planted 55 gallon. They did live peacefully with the adults.
.
Also, as a predator, Amatitlania myrnae display no actual hunting behavior as the action all happens crepuscularly.

 

[jjohnwm]

Umbra mudminnows are long, cylindrical, flexible...no spines...round head without any projections or large teeth...they practically have "Eat Me!" tattooed on them!

And, let's face it...there are no particularly extreme predatory skills required to catch a small fish when the predator and prey are confined in a small tank where they cannot ever get more than a foot or two apart from one another. The little guys have to survive every single one of their close encounters...the big guys only need to get lucky once to be the ultimate winners. As aquarists, we make it just so easy for the eaters, not so much for the eatees...

 

[Jexnell]

Maybe look at one of the more peaceful Amatitlania sp.
This is a 40b I had running for about two years. I started with 6 plattys and two Honduran redpoints. There were 5 vals, 2 Amazon Swords and 4 stem plants.
This is what I started with. No ferts were used, no CO2. The light was a Finnex planted plus 24/7 the substrate was Caribsea planted plus. The tank did get some late afternoon direct sunlight.
A couple months later

At the six month mark. And absolute explosion in plant growth. As well the fish multiplied both the HRP'S and the Plattys.
At the one year mark the tank was overrun by both fish and plants. I took out all the plants, removed all the non vals as they were getting light starved.
That is my shower curtain folded in half for scale.
Some of the vals were hitting 6ft in length.
I took out half the vals and then replanted, this time it was platinum convicts and six plattys.
And again by the one year mark it's was massively overgrown and over populated with fish.
Even with these insane numbers of fish for a 40b there was no measurable nitrates.
I lived in Portland Oregon, so the amout of afternoon light was an hour or two at the most till summer then maybe three hours. The patio door behind the tank faced Northwest.