Corals & Co. 2
Tiny feather duster worms such as Bispira viola (approx. 35 mm) often find their way into Nano Cubes unnoticed, together with the living rock. They reproduce asexually there, sometimes forming dense groups. They filter plankton out of the water with their garland of feeding tentacles, which lends them a flower-like appearance. Calcareous tube worms such as this Microprotula ovicellata (approx. 30-50 mm) may also enter the Nano Cube together with living rock, on which they breed abundantly.
Bristle worms are related to earthworms. While their appearance may not be to everyone's taste, they are extremely useful in aquaria as they eat feed residues and other waste, loosening up the bed in the process. Some varieties also clean up algae from the glass sides.
If there is insufficient food in the aquarium, they may set to work on the corals, however. Larger bristle worms in particular should therefore be removed from the aquarium.
Do not touch with your bare hands - the bristles can cause "burns".
The Asterina burtoni starfish measuring 10-20 mm in size are interesting candidates for the Nano Cube. As primarily nocturnal grazers they eat epibacteria from rocks and the glass sides of aquaria. Asterina burtoni starfish reproduce by division. Missing arms subsequently grow on the next generation - a fascinating spectacle. They should be kept in check to prevent them from breeding too abundantly, however.
Little serpent stars also easily find their way into Nano Cubes together with living rock. They reproduce by division. The Amphipholis squamata measuring only around 10 mm in diameter actually reproduce sexually. Serpent stars are omnivores, also devouring residual feed and waste. They are fond of sitting in narrow gaps, from which just 1 or 2 arms stretch out in search of food.
Sponges come in a great variety of shapes and colours. They live by filtering fine suspended matter out of the water. The photograph shows a blue sponge of the Haliclona variety.