Well said Venom SS! They are a tough fish not an obedient dog. All the fish that You are inquiring about Goldenballer are not agamy fish hence they would really enjoy a mate of the same specie. I am curious why you want a solo fish? If I could curb or convince you to get a pair it would be Managuense "Jags". A pair can be active,curious,and happy not bored.... Get what I mean. What ever Monster you chose get a pair unless they are truly a hit and run fish that doesn't require a life mate but even then I would do my best to find a tank mate so they stay busy. Good Luck with your tank!