how fast could you compair a geo to a diferent fish, do they gro faster then tangs do, or slower then FM's and could i have 3 juruapari or sirenamensis in a 55 gallon, with some dithers and some loaches, or would it be better to have some taphjos
Hi there! Would the 55g be for life? If so a 55g would not hold S. jurupari or G. "surinamensis type" for life. I'd have at least a 125g tank. If you want geos for 55g I'd try either Orange Head Tapajos or pindare. Or you could even setup a Uruguayan and put in Gymnogeos.
As for growth rates it depends on the species and the care given. I havent kept the geos you mentioned (mainly cuz I dont have a tank for them) but from what I've read they are not very quick growers.
I'll go one step further here and expand on what Abarilot has said ^ above.
For a 55 gallon there is not a Geophagus ("surinamesis types" Altifrons, Abalios, Dicrozoster etc..) species or Satanoperca ("Jurupari types") species that can spend their life in a 55 gallon tank as they can and do reach 10"+ in adult size, that includes G. 'tapajos' & G. Pindaire as well as although they max around 6"-7" range. There are species however from the geophagine complex (eartheaters) that could do OK in a 55g.
Guianacara such as G. Guaeyi would do OK with a group of 4-5 adults. Biotodoma either B. Wavrini or B. Cupido could almost fit but likely would fair better in a 75-90 gallon tank. Any reason you cannot get a larger tank? GL