Fish

[VOX]

About how many fish can you comfortably fit into a 20g tank? Preferably mollies or any livebearers.
Thank you.

 

[seanc]

It depends entirely on the fish but an inch per us gallon is a rough rule of thumb, so 20 inches of fish.
so sailfin mollies or dalmation or balloon?
take adult inches and total them. should be less than 20.. applying only to small slim bodied fish without any territorial or other requirements (such as tank length... kinda inaccurate as I'm sure you can tell. a few nice calculators for working it out though such as at thinkfish.co.uk

 

[VOX]

I tried the stocking calculator for 20g and converted gallons to liters( 75.71 according to an online translator) and it said 50 gallons. (External filter)

How is that so?

 

[seanc]

External filters allow you to exceed the limit.. pretend you have a basic internal filter not an oversized external. The added filtration allows you to stretch the rule significantly.. but as a newbie you wont want to do that

 

[dwarfgourami]

It's not just about filtration but about swimming space too. A sailfin molly is a big fish- they will need more than a 20 gallon tank to stretch their fins. But if you go for platies and guppies and the smaller types of mollies, you could comfortably fit in about 10 fish. Just think about the sex ratios and potential fry. Either females only, or 2-3 females per male, or not fewer than 5 males (to spread aggression).

And btw, the thinkfish calculator does not follow the 1 inch/gallon rule, but a much denser stocking ratio- IMO too much for a newbie + they do not always consider the swimming and/or territorial needs of the fish.

How are you cycling the tank? If you use the livebearers to cycle, you need to start with only a couple.

 

[seanc]

"20 gallon tank"

a 20 gal long would be enough for them to swim comfortably. 3foot tank for a fish that will max out at around six inches.

I know thinkfish does allow too much for a nebie thus the suggestion to put down an internal as opposed to the exteral filter they are using.. would compensate.