How many more fish can I get?

[Apple678]

Hello, I have a 65l fish tank, and I was wondering if I’m getting close to being overstocked. I have 2 platys (both female) and 6 gold tetras (idk about the genders). I was wondering if I could get more fish, or is it coming to the limit. I was thinking I could get a betta? I know they aren’t great for community, but would it be fine with tetras and platy? If not what other fish/creatures could I get. Thanks
(Tank is 25°C, and planted)

[ColdKoi]

I’d suggest using the aqadvisor calculator. Great little tool for playing around to see your stock load

Keep in mind stock limits are not exactly a hard line, if you’re overstocking(within reason) with fish of the appropriate size for the tank it merely means more maintenance

[Joe_D]

An old rule of thumb is an inch of fish for every gal
However, that is pretty arbitrary as there are variables involved.

How big is the water column..... how much water is eliminated with big rocks etc ?
What kind of fish are they? Some are much dirtier than others..
How much free time do you have to do maintenance like water changes etc?

So, one must do some research on the fish they want to get.
Also, add more fish a little at a time and keep a close watch on the Nitrates.....keeping in mind that Nitrates are not nearly as toxic to fish as Ammonia and Nitrites are......
and that Nitrates are necessary for plant growth.

Most all tanks are a bit different and what may be overstocking in one is not in another
So only a given tank owner can really assess if their tank is overstocked or not .

[ColdKoi]

Exactly. Over stocked is pretty subjective, of course there’s just blatant overstocking where water quality cannot be maintained. But within reason, your stock limit is limited more by the ammount of work you want to do to maintain the water quality of the tank. Whether that’s more filtration and/or more water changes, it’s really a question of how much work you want to do.


I’ve got a ridiculously overstocked 29g with comets I’m growing out for my pond next summer. It’s running a 70g sized hob filter with a pre filter sponge and a deep substrate. It’s not ideal for long term by any means, but weekly water changes keep the water quality in a nice range and if I have to, I can push it another week before nitrates start getting pretty high. being a short term situation, the extra work isn’t really much burden, though I wouldn’t want the same situation long term as that would just make it feel like work!

[Joe_D]

BTW..... about a Betta
I once had Betta in about a 30 g community tank and, found that there was no problem.... as long as they are about the last to be added as they are somewhat territorial.

Being the last to be added, they will have no territory to defend. They will usually just find a spot to hang out when they want to rest

A 65l tank (about 17 gallons) is most likely big enough for a Betta. so it will not feel crowded .
Just make sure there are no fin nippers in a tank.

[Joe_D]

Also......
Do you have any bottom feeders to eat and clean up any food that falls to the bottom?
Uneaten food that frequently falls to the bottom can be a real problem when you want to add more fish.

I recommend at least two or three three Cory catfish for this. They will also search the leaves of plants for uneaten food.
They are small, , are not only great tank cleaners, they are cute. Contrary to popular belief, they are equally at home on gravel as they are on sand.
.
Granted, Cory cats create their own waste but they eliminate other waste hopefully making them well worth while
Everything in a tank is a balance between things.