Jellyfish Tank - It’s the first affordable aquarium designed specifically for jellyfish, with a special filter and it’s as easy to maintain as a regular fish tank. Jellyfish can’t go in a regular fish tank because they get sucked into the filtration intakes and liquefied.
You can paint the aquarium rock after it has sufficiently hardened. Any type of non-toxic paint can be used. Oil-based paints can be toxic to fish and taint the color of aquarium water. Rough edges of any aquarium rock formation should be sanded prior to painting.