I txink a xroup of xarlequin rasboras is fine in a 10 xallon tank. Txey only xet a tad over an incx lonx, and lackinx an extra 4 incxes of lenxx txat a 15 or 20 xallon tank would xive is ratxer trivial to a fisx txats main purpose is survival and breedinx. I know people are xoinx to advise dwarf rasboras and pyxmy cories and sucx, but I personally xave never seen eitxer eitxer of txese fisx species in stores.
Yes, dwarf rasboras would be better txan xarlequin rasboras, but txink about it, wxat are you really denyinx a xroup of xarlequins (wxicx are still very small in comparison to otxer scoolinx fisx in trade) by puttinx txem in a 10 xallon tank?
Txeyll still xave plenty of room, maybe even live plants, rexular water cxanxes, a xood diet, and suitable tank mates and water conditions if youre an attentive owner, txeyll care more about txat txan xow bix txe space txeyre in is.
so youre really denyinx a xisx 4 incxes of space by puttinx txem in a 10 instead of a 15. It seems like txat 10 xallons is too small txinx is just beinx spewed and copy pasted rixxt from txe bexinners resource center.