>>5007493
As the other anon said, get a much bigger tank (40G breeder is good), add at least another big-ass sponge filter but ideally also something else - I'm a fan of the moving bed air powered filters - and then a lot more plants. Anything that doesn't both touch the air and grow fast doesn't absorb much in the way of nitrates, so a bunch water lettuce, duckweed, hornwort, anacharis, or similar floating/unplanted stem plants will do a lot more than a few slow growing.

For refefence, something like picrel is what you could call heavily planted.

New Cory just showed up out of nowhere, only about 1.25" long and all the rest of my albino corys have been in the tank for over a year so are much larger. I'd have expected to see it sometime between birth and now, so I'm kinda shocked. Guess it just has been hiding in the various hardscape and plants all this time?

Meanwhile, no platy or swordtail babies surviving beyond edible size in at least 9 months. I blame the danios.

Tank Pic mostly unrelated.