16-05-2022, 14:51
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Casella atromarginata is a mollusk known to tropical fish lovers as the blue velvet holodermen, blue velvet sea slug, or sea slug head. The habitat of this clam is the western part of the Pacific and Indian Oceans. Keep these clams are recommended only experienced aquarists.

Blue velvet holojabernik - is a peaceful mollusk, leading a mostly crepuscular lifestyle, which spends all waking hours in search of flatworms, which it feeds on. Clams can secrete poisonous toxins as a defense mechanism when threatened, and should not be kept with aggressive predators who may view them as food.

Casella atromarginata has a hammerhead and a beautiful velvety black body with bright blue lines highlighting the edges of the body and the middle of the head. The maximum size is 7 cm.

Casella atromarginata

If you have a flatworm problem in a reef aquarium, you just have to put in a blue velvet holojabernik. Molluscs are best kept in a reef aquarium of 80 liters with lots of live rock, sandy substrate and a large colony of flatworms.

They do well in established reef aquariums and are reef safe, but they may need additional nutrition due to the lack of a significant flatworm colony. 

Like most invertebrates, the blue velvet holodermen require consistent water quality, as they are very sensitive to rapid changes in water conditions. The clams are especially sensitive to high levels of nitrates and cannot tolerate any amount of copper impurities in the water. After acquiring clams, they are placed in an aquarium with the lights off. The acclimatization period is quite long.

Casella atromarginata.

Water parameters: temperature 22-26° C, hardness dH 8-12°, acidity pH 8,1-8,4, salinity 1.023-1.025.

The main menu of mollusks in an aquarium environment are flatworms, which they eat, using their proboscis-like tube to suck them up. Without a steady diet of flatworms in their diet, they will generally not eat anything else and will begin to starve, which will eventually lead to unfortunate consequences.



In established reef aquariums, Casella atromarginata regularly spawns frequently, but aquarists do not report successful larval rearing.

The blue velvet holojabernik is available to marine aquarium enthusiasts in specialty stores and online.

Casella atromarginata


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