me and my older brother owned this type of fish before.. they kinda just swim against the current, or constanly swim in circles.. kinda pricy too.
theyre were called blue torpedo sharks, or blue dolphin sharks.. dont know that official specie name, sorry.
these fish are BLIND and are carnivores, they eat what they sense in the water. by swimming in circles, and whatever change in the water they go that way.. interesting fish, i would get them again, just cant have smaller fish in there with them like tiger barbs.. my older brother had a school of barbs about 10, 3-4 inches, and they got knocked out..
were you planning on buying it? you have to get atleast two. it looks like sharks lurking in circles, i bought a sunken ship just coz of them, and it looked bad ***. they go thru the lil holes and lurk like the movies.. hahahah. these fish are rarely available out here in the bay area, so when i see them again ill get me a couple for another community.