New Tankmate?

I want to get a Dalmatian molly, the tank is 20 gallons, already cycled and has had fish in it for quite some time now. At the moment all I have is 4 black skirt tetra, 1 black molly, 1 corey cat, and a red tail shark. Would one more Dalmatian overstock the tank? If so is there anything else I could look into getting that won't be a problem? I was thinking neon tetra but I'm not sure how the black skirts would react...

P.S. I know red tails get large and may outgrow a 20 gallon. I'm fixing up a 100 gallon tank to put him in later on.

 

You could definitely add another single mollie but you really need to add several more cories until you can move them to a larger tank and then add a few more. They are one of the schooling fish that really need more of their kind compared to other schooling species.

 

Is it a 20 high or 20 long?

Red tails will DEFINITELY outgrow a 20 gallon. A 100 gallon won't even be enough - those guys need upwards of 2000-3000 gallons or more, and they grow FAST. I'd take him back to the store ASAP - they're really not fish that should be sold in the hobby. They can get to almost 6 feet long.

I'd recommend filling out what you have before adding anything else. For example, I'd recommend you get at least 2-4 more black skirt tetras, as they're schooling and will definitely do best with more in the tank. I'd say a 20 gallon is a bit small for them full-grown, but I think they'd be better off a bit cramped with more of them than having more space with less.

What kind of cory is he? All cories are shoaling, and need to be in groups. Assuming you have a smaller species, you should probably get 4-6 more.

As for the molly, assuming that you get rid of the red-tail, you could get a male molly. I'd advise against a female, as you're going to have tons of fry, and that's going to add bioload to an already slightly overstocked tank (IMO).

 

You could definitely add another single mollie but you really need to add several more cories until you can move them to a larger tank and then add a few more. They are one of the schooling fish that really need more of their kind compared to other schooling species.

Well I started out with 3 cories, both of the albinos died pretty early on, I was planning on getting a couple more eventually, I was just worried about having too many bottomfeeders, because isn't the red tail a bottomfeeder as well? and I heard they can be pretty territorial.

 

You are correct. But again with cories more specifically they do best in schools over 8 strong. You can get away with your skirt tetras in that small of a school but not them. The red tail is a carp and it grows like one. Like goldfish though it will only grow to its environment but they do need a bare minimum of about 75 gallon to do well. Otherwise you will stunt it and it won't thrive and will probably die early.

On a side note, the skirt tetras and neons would probably do well together as long as you had large enough schools of both and a larger tank for them. What you have would be a good species only tank for the skirt tetras with a few mollies.

 

Is it a 20 high or 20 long?

Red tails will DEFINITELY outgrow a 20 gallon. A 100 gallon won't even be enough - those guys need upwards of 2000-3000 gallons or more, and they grow FAST. I'd take him back to the store ASAP - they're really not fish that should be sold in the hobby. They can get to almost 6 feet long.
(IMO).

Red tailed Shark not Red tailed Cat. But I agree the Cat's should only be sold to specialists.

 

Is it a 20 high or 20 long?

Red tails will DEFINITELY outgrow a 20 gallon. A 100 gallon won't even be enough - those guys need upwards of 2000-3000 gallons or more, and they grow FAST. I'd take him back to the store ASAP - they're really not fish that should be sold in the hobby.

I'd recommend filling out what you have before adding anything else. For example, I'd recommend you get at least 2-4 more black skirt tetras, as they're schooling and will definitely do best with more in the tank. I'd say a 20 gallon is a bit small for them full-grown, but I think they'd be better off a bit cramped with more of them than having more space with less.

What kind of cory is he? All cories are shoaling, and need to be in groups. Assuming you have a smaller species, you should probably get 4-6 more.

As for the molly, assuming that you get rid of the red-tail, you could get a male molly. I'd advise against a female, as you're going to have tons of fry, and that's going to add bioload to an already slightly overstocked tank (IMO).

Its 20 gallons long, I started with 3 cory, 2 albino and one just looks like a normal corey, albinos died fast, was definitely going to get a few more though, just worried about having too many bottomfeeders with the red tail. I had no idea red tails need that big a tank, its a shame cause hes my favorite and the only one of the bunch with a name lol even the tags at the store say at least 29 gallons.
And my only thing with the black skirts is I've had them in pretty much all my tanks throughout the years and id like more variety.

Red tailed Shark not Red tailed Cat. But I agree the Cat's should only be sold to specialists.

Yeah, I am in no way a specialist

 

My bad - long day! Red tailed shark is definitely a different beast, lol.

Red-tailed sharks do need something bigger than a 20 long, IMO, but not the several thousands that red tailed catfish do.

 

Its 20 gallons long, I started with 3 cory, 2 albino and one just looks like a normal corey, albinos died fast, was definitely going to get a few more though, just worried about having too many bottomfeeders with the red tail. I had no idea red tails need that big a tank, its a shame cause hes my favorite and the only one of the bunch with a name lol even the tags at the store say at least 29 gallons.
And my only thing with the black skirts is I've had them in pretty much all my tanks throughout the years and id like more variety.

Don't worry your species will only get around 6-8"

 

You are correct. But again with cories more specifically they do best in schools over 8 strong. You can get away with your skirt tetras in that small of a school but not them. The red tail is a carp and it grows like one. Like goldfish though it will only grow to its environment but they do need a bare minimum of about 75 gallon to do well. Otherwise you will stunt it and it won't thrive and will probably die early.

Well like I said, I'm only keeping the red tail until the 100 gallon tank is fixed up and ready to go.
Ill definitely pick up some more corey though, I like my fish happy.

My bad - long day! Red tailed shark is definitely a different beast, lol.

Red-tailed sharks do need something bigger than a 20 long, IMO, but not the several thousands that red tailed catfish do.

Its all good man, we've all been there rofl, I'm just happy he won't be going back to the store.