What If?

[wilkesy88]

If you can fill up your filter completely with used/mature filter media , sponges or ceramics ect, then you can add a couple of fish almost straightaway as the media will already be full of bacteria and effectively be mature.

Then after a week or two of the filter bacteria getting used to the waste produced by a couple of fish, you can add 1-2 more.

To be honest your tank isn't really suitable for the fish you have. Barbs do better in groups of 6 or more, as do tetras who like groups of about 8 or more , and you don't have enough space for groups of all the fish you have . You'd be better off taking the fish back to the shop and getting ( or actually demanding if you have the reciept ) a refund, or rehoming them with someone who has room for them . A tank your size is better for 3-4 guppies or endlers, or a betta.

And since your tank basically isn't cycled at the moment , if you take the fish back you can do a proper cycle without harming any fish in the process.

they wouldnt take them back, a friend tried that with his.

 

[Honeythorn]

Do you know anyone who can take them on? Does your friend have space in his tank?