have 2 erys at 6".put them in with 3 chevron snakeheads approx4-6.5" .after a few hours due to the hyperactivity of the SHS,the erys started to try TORPEDOING up n out of the aquarium,banging loudly the aquarium cover.i quickly separated the 2 erys from the SHS and into their own tank.....ALSO,its not a good idea to keep multiple erys 2 gether.the smallest n least aggressive ery will surely die from bites to the tail.TOO much competition = eliminate competition..TRUST me.it happened twice.i had 13 erys now only 11 are remaining.9,i have since given to relatives.......hope this helps.........regardsteggner;2911032; said:Anyone know if they go well with channas and polypterus?