Adding Fish

[Kemics]

i have a 56 litre tank, in the tank at the moment i have 3 platys and a comet goldfish, in total about 20cm worth of fish. Am i right in thinking that its about right to have 1litre of water for every 1cm of fish.

I would really like to add some white cloud mountain minnows as they are aesthetically pleasing and wont mind the coldwater temps. I was hoping to fit 10 and a pleco into my tank, by my math this is within the tanks capacity, is that right? What im more worried about is whether my comet will behave himself. Im told they can actually be quite territorial. I havnt had any trouble so far but i was told that might be because there is alot of space in the tank for 4 fish at the moment so he dosn't feel threatened. However, at one point i had another goldfish, the comet and the 3 platys in a 25 litre tank, but gave one of the goldfish away because the tank was over stocked, but even then i didnt have any trouble with them behaving.

all thoughts appreciated

 

[minxfishy]

Hi, you shouldnt really be mixing coldwater fish and tropical fish, the heat that the tropicals require will not be good for the comet. However people do it, your not the first.

WCMM can be kept in coldwater tanks no problems but be careful with the comet as they can and will eat smaller fish. Personally I would suggest you remove the comet as really he needs 20gallons just to himself, so isnt really suited to the tank at all, maybe find him a nice pond he could live in happily with other goldfish.

 

[Kemics]

yeah, this is a problem i keep encountering. I would like to use my heater for the platys, i hear coldwater isn't great for their immune system/general well being but only found this out recently as they have been in the tank for a year now. Tank temp is usually 21c.

if i were to put my comet in a pond would he face any issues having been in a tank his whole life (its my flat mates fish ive adopted as she was neglecting it) and she wants to make sure he'll be okay

 

[malakye]

The goldfish would be better in a tank of his own or in a pond he will settle in either fine so long as he is introduced to it properly and not just dropped into a pond which is much colder than he is used too. Platys would be better with a heater and becareful what plec you buy as you dont want to end up with a monster in your tank.

 

[Kemics]

what plec you buy as you dont want to end up with a monster in your tan

do you mean size wise or behavior?

is this a bad time to introduce a goldfish to a pond in mid winter?

I keep hearing for reliable sources that goldfish are really pondfish and just arnt suited to tanks, especially small community ones. So how come petshop sell them so often for just this?

 

[OldMan47]

At 21C, the platies are about as cold as they can be and still be comfortable. They will show better colors at 24 or even 25C but at 21C they will be OK until you can separate them from the cold water fish.
Unfortunately, your original question has the answer that a comet by itself is a full stocking for a 56 litre tank. For small fish like platies that don't get more than about 5 cm as adults, the formula will leave you OK but a bit heavily stocked. For a large fish like a comet, at over 30 cm, the formula falls apart completely.

 

[Kemics]

my comet hasnt really grown too much, he seems to be roughly 10 cm long i reckon and has been since i bought him.

 

[RushingChamp28]

At 21C, the platies are about as cold as they can be and still be comfortable. They will show better colors at 24 or even 25C but at 21C they will be OK until you can separate them from the cold water fish.
Unfortunately, your original question has the answer that a comet by itself is a full stocking for a 56 litre tank. For small fish like platies that don't get more than about 5 cm as adults, the formula will leave you OK but a bit heavily stocked. For a large fish like a comet, at over 30 cm, the formula falls apart completely.

OldMan gives some good advice here. The "time tested" formula of length of fish per volume of water is a very rough guideline at best, for example a 12" tinfoil barb has about 50x the biological demand of 12 1" neon tetras, even though according to the rule they count the "same" toward the final amount of fish. Keep that in mind...