Jellyfish have long been on the wish lists of eccentric pet collectors and precocious kids, but until now their viscous figures rendered them too vulnerable to the suck of traditional in-tank filters. Thanks to Brooklyn-born, San Francisco–based Alex Andon—whose tanks borrow a Scyphozoa-safe circular-water-flow technology used by public aquariums—these aquatic acrobats are now primed to become apartment fixtures. Get started with the eighteen-by-fifteen-inch Desktop Jellyfish Tank ($499 at Dijitalfix, 218 Bedford Ave., at N. 5th St., Williamsburg; 718-388-2720), which includes an air pump, a feeding pipette, a six-month supply of plankton purée, and a color-changing LED light that illuminates both the tank and its translucent, pulsating inhabitants. You’ll also get three free non-stinging Moon Jellies that are shipped live overnight from Andon’s San Francisco breeding facility, Jellyfish Art.