He is about a cm in length, about a year old, has a half black half red dorsil fin, and is a deeper red than he appears in the photo's below. He / she hasn't grown at all since we have had him and I assume he scavenges uneater food at the bottom of the tank as I have never seen him eat.
On the right below is a standard 6mm air hose to give some idea of size.
We got this fish by mistake, it came with 10 harlequins. He occasionally tries to school with my neons, so I would like to get a few more of these so he has some friends to scholl with.
Any help much appreciated. Thanks

On the right below is a standard 6mm air hose to give some idea of size.

We got this fish by mistake, it came with 10 harlequins. He occasionally tries to school with my neons, so I would like to get a few more of these so he has some friends to scholl with.
Any help much appreciated. Thanks