i realize this is a natural and physical improbabtility, but i was taking bong rips and decided it would be generous to give the fluffster a few shotguns. it works on people and dogs and cats and stuff...........so i would take a ripper and exhale it into the air intake hose on the powerhead that ordinarily inhales air from outside the tank to add additional air to the water in the tank. this air is then "strained" by fish gills to aid their respiration as the delivery vehicle for 02 entering their little bloodsteams. so i blew a few huge (read 8 or 9) hits down his hose which basically made millions of tiny thc filled bubbles rise up around him for about ten straight minutes as i smoked and smoked out the fish's tank. your smoke rises as air would toward the surface which settles like fog on a medieval swamp and hangs about an inch or so off the surface between your water and the lid or hood. it's delightful really; to see it swirl and whisp around inside your tank. anyway, i repeated this process several times. use your best judgement. the fish's tolerance is probably way lower than yours anyway. i'm not saying he got high or anything, but the aeration in the tank was solid pot smoke for a good while and he was breathing as usual right in it's path the whole time. afterward i swear to god he was up at the front of the glass, nose right touching it for the rest of the night just staring out of the tank and just hovering there all golden colored and sh*t. is eye is already reddish so that's a tough call. he definitely likes to check out the tv, playstation, people in the room , and my dog when he's like that. usually he doesn't get all laid back like that until late at night when it's dark and he's eaten. you make the call. it's fun to try anyway. i wouldn't do it often because it not cool to do to your water with all the impurities in there and all, but doing it once in a 55 gal? big deal.