Is My 20Gal Tank Too Small?

[kiira]

I have a 20 gallon tank with 3 Silver Lyretail Mollies, 1 Black Lyretail Molly, 1 Swordtail, 1 Balloon Platy, 1 Sunset Platy, 2 Dalmation Mollies, 1 Gold Dust Lyretail Molly and an Albino Corydorus. I was hoping to get 2-3 more Corydorus fish so that it would be kept more clean from them feeding on the sunken flakes at the bottom. I also wanted to get a couple Guppies and maybe another platy. Is my tank already too overstocked? I'm trying to get more live plants also for water clarity but the tank seems to be doing pretty well for now.

 

[MrGT500]

i think you would be fine adding a few more corys, and they like to be in groups so you probably should. the other fish swim at the top of the tank and the corys are bottom feeders so you should be fine, given that you have good filtration.

 

[sadguppy]

I would say you're extremely well-stocked. Well, overstocked really. Mollies in particular are big fish and will outgrow that tank eventually. You might want to consider an upgrade.

 

[Smells a bit fishy]

Cories are very social fish and do far better when in groups of 6+ if you can rehome a couple of mollies and the platies I would then up the cories to 6. But I think you are fully stocked as it is.

 

[N0body Of The Goat]

An upgrade to at least a 3-foot, if not a 4-foot (a 140l 48x12x15 would suit the bill nicely) would be my choice, as Mollies (especially females) become quite chunky ~12cm and like many livebearers they can become a bit fiesty at times. A longer tank would give them room to use more energy and have chance of finding some respite at times of any aggression.