bristlenose are great cleaners have 1 for my 10 and he does an amazing job. as for other fish for a 20 5 longfin zebras would be good and a gourami or 2. If you go with 2 gourami's male and female. Have a 20 with that stock well a few more longfins 10 to be exact.

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20 Gallon, 6 zebra dinos, 4 green tigers, 3 dojo loach's, 2 blue gourami's, 2 GBR's, 2 bristle plecto's, 2 longfin rosybarbs, 1 syno cat, 1 leopard puffer
25 Gallon, 2 clown loach's, 1 yoyo loach, 1 veil angle, 1 royal plecto, 1 female krib.
36 Gallon bowfront, 1 Green Severum, 2 Auratus, 1 Venustus, 1 Acei, 1 Kenyi, 1 Duboisi, 1 Demasoni, 2 other africans I haven't identified, 2 Pictus Cat, 1 Rainbow shark, 3 tertas, 1 Firemouth cichlid