Well your in the arowana forum and I can tell you that the silver aro will need at least a footprint of 8'x30" but 8'x3' would be better with tankmates. Also the combo of aro and gar can end badly. For tank size and compatibility for gar you may want to ask the good folks in the gar forum. Two motoros may need even a bigger tank, check in the ray forum. Once you decide on a tank size you may want to post a thread in the DIY forum for help with your build.
Best thing is not to be lazy and do some searching and research alot of the knowledge for yourself. Cause IMO your base knowledge regarding any of this is very low.
Best thing is not to be lazy and do some searching and research alot of the knowledge for yourself. Cause IMO your base knowledge regarding any of this is very low.