24" x 12" x 16"Before any credible stocking suggestions can be made, we'd need to know about the water the fish would be living in;
pH
Hardness
Also, the actual dimensions of the tank, other than just 20 gallon.
Fish are generally happier in waters that haven't been artificially tinkered with.24" x 12" x 16"
Have water on the softer side and a ph of around 7.3
however am willing to buffer water as I've done for shell dwellers
I like the idea of more Tangs but I think your tank is a bit small for Calvus, I'd want somthing more like 3 foot long or a bigger base than 24x12. Which shell dwellers have you got already? How about a different kind of shell dweller like an Ocelatus Gold?24" x 12" x 16"
Have water on the softer side and a ph of around 7.3
however am willing to buffer water as I've done for shell dwellers
have multis, have had my eye on ocelatus but heard can be quite aggressive. But i suppose in a 20g have enough room. I do have a 3 foot tank that i was thinking i could use for calvus and synodontis (if you have thoughts on anything else i could add please tell). Ocelatus are rather hard to come by around me, seem to only be males available but definitely something i'd look intoI like the idea of more Tangs but I think your tank is a bit small for Calvus, I'd want somthing more like 3 foot long or a bigger base than 24x12. Which shell dwellers have you got already? How about a different kind of shell dweller like an Ocelatus Gold?
Wills
If the three foot is a good foot print it opens up a couple of other species Caudopunks are really cool, you could try Calvus or similar species (Blacks are awesome) with them. A couple of the rock dweller species could work in a 3 foot like Julidichromis or some of the Neolamprologus.have multis, have had my eye on ocelatus but heard can be quite aggressive. But i suppose in a 20g have enough room. I do have a 3 foot tank that i was thinking i could use for calvus and synodontis (if you have thoughts on anything else i could add please tell). Ocelatus are rather hard to come by around me, seem to only be males available but definitely something i'd look into
soft water ain't no good for calvus and as @Bruce Leyland-Jones said, most fish don't like artificially buffed water. Also, calvus need at least 30 gallons so you are 10 gallons short.24" x 12" x 16"
Have water on the softer side and a ph of around 7.3
however am willing to buffer water as I've done for shell dwellers