Overstocked 112l tank

[Lennys]

Hey guys,
I have recently made an mistake and overstocked my planted tank, that was already overstocked a bit.. My colleague wanted to throw away 15 young cardinal tetras, so I had to take them.. According to AqAdvisor my filtration capacity is 269%, the rest pls see the picture. The fish are all juveniles. Nitrate levels are very much ok, change 50% water every week, use RO water, keep GH around 4 and KH around 3.
Attaching a photo of the tank too, although the plants have grown a bit since it was taken.

Should I start searching for a new tank fast and move at least the cardinal tetras+otos with some amanos?

 

[Beastije]

Luckily tetra are low bioload fish. I would just up your water changes to every 4 days and add some floating plants to help leach out nitrates faster
If you do not want to do this for the rest of the tank existence, get a new tank I would move the insufficient-number corydoras that also should never be with apistogrammas if they are breeding and one or two tetra schools.
You are risking killing off this tank with a simple mistake, one slight overfeeding, one missed water change because you have a cold, one day where the temp are too high and the oxygen production isnt enough and you have a disaster.
I would also invest in a air pump just for an air stone, overnight your multitude of fish cant be covered by the plants cause there is no oxygen production, so at least for a night an air stone should be running in my opinion. You could verify that if you notice at light start all the fish are in the upper part of the tank or "gasping" but not the same behavior during the day

 

[AdoraBelle Dearheart]

Fortunately, your fish are still juveniles, you have a lot of beautiful, healthy and growing live plants, and you're staying on top of water changes and tank maintenance, so all of that helps.

Aqua advisor is more of a guide than an absolute... and it doesn't account for a lot of factors like the live plants, skill of the fishkeeper, how often you're doing water changes etc. So don't panic and think "emergency!" because of aqua advisor, even though in the long term, yes, you will need to make some changes because it is overstocked, and will become an issue if you miss a water change, or a fish dies and causes an ammonia spike, or as the more territorial fish mature and begin wanting to breed.

If you do decide to get a larger tank, or just a second tank to move some of the stock too, don't, whatever you do, move the otos first. Otos need an established tank with plenty of biofilm and soft algae to eat, and this isn't available in a new set up. Go with @Beastije 's advice and move either the cories, or the apistos, since they shouldn't be together. Apistos are ground level and territorial, especially when mature and wanting to breed, and cories are bumbling ground dwellers that don't even grasp the concept of territories, so are likely to both annoy the apistos, and be bullied by them. Not a great mix to have.

If you want to move the otos later, by all means, but make sure the tank is fully established (which takes 3-6 months minimum) and that you've cultured the tank so they have food stuffs on the tank glass, the live plants, driftwood etc, first.

An experienced and dedicated keeper can often manage a tank that is technically overstocked. But it takes experience and dedication precisely because things can go wrong so quickly in a tank that's overstocked. Be strict about your water changes in the meantime, increase them in both frequency, and water volume changed, and keep an eye on those water test results so you know how often they must be done.


The key to managing a tank that's overstocked is lots of healthy, live, fast growing plants, over-filtering (and having two filters on it would be wise, especially in case one fails, the other can buy you some time to find and fix the problem, before you're facing a full tank crash). And up the water changes according to need.

I can see why you took in the tetra, and it looks as though you'll be able to manage, so no criticism here! Especially since they're still small, not highly high bioload, and your tank looks as though it can handle it for now. But yes, long term, it's worth getting another tank, or a larger tank to eventually transfer all of them too, but again, the cories and apistos would be better off in separate tanks in the long term.