Blue Velvet Nudibranch

Chelidonura varians

Saltwater Invertebrate Species Group: Sea Slugs Family: Aglajidae

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Water parameters

Temp 76-80 F Temperature

Maintaining a stable and appropriate temperature is critical for the survival of aquatic life.

pH 7.8 - 8.4 potential of Hydrogen

Measuring the acidity or alkalinity of water on a 0–14 scale, where 7 is neutral, 7 is alkaline.

NO3 1-20 ppm Nitrate

While less toxic than ammonia, high nitrate levels (above 40–80 ppm) are important to monitor because they can cause fish stress, stunted growth, and harmful algae blooms.

NO2 <0.0001 ppm Nitrite

It is a highly toxic, intermediate compound in the nitrogen cycle produced from broken-down ammonia

PO4 0.01 - 0.1 ppm Phosphate

It is essential for plant development but must be managed, as excess levels trigger nuisance algae blooms and inhibit coral calcification.

NH3 <0.1 ppm Ammonia

It is the primary killer of aquarium fish, causing gill damage, stress, and death

Ca 380 - 450 ppm Calcium

Supporting the growth, skeletal structure, and shell formation of corals, mollusks, crustaceans, and coralline algae

KH 8 - 12 dKH Alkalinity

It acts as a shield, neutralizing acids to prevent dangerous pH "crashes" that can harm fish, corals, and plants.

Mg 1200 - 1400 ppm Magnesium

It enables coral growth by supporting skeletal formation, assists in metabolic processes, and ensures that calcium is available for corals, clams, and coralline algae.

SG 1.023 - 1.026 SG Salinity

Essential for maintaining stable, natural water parameters, proper osmoregulation, and stress-free environments for marine fish and corals

ORP 250 - 400 mV Oxidation-Reduction Potential

A higher positive mV indicates clean, oxygen-rich water with high water quality, while low readings indicate high pollution.

About Blue Velvet Nudibranch

General information

The Blue Velvet Nudibranch is black in color with blue lines around the outside of its body and down the middle of its head. It has a hammer-shaped head and two appendages at the rear, mimicking a flatworm. This specialized eater will consume flatworms in the aquarium. It sucks up the flatworms using a tube-like proboscis and makes a great natural alternative for flatworm control. However, it must be provided with a steady diet of flatworms in order to thrive. In addition, it is sensitive to rapid changes in water conditions and does not have a long life expectancy. Because of this, only expert aquarists should attempt to maintain this species. Spawning occurs regularly when more than one of this species is maintained together. Unfortunately, there has not been a good success rate reported in raising the larvae. The Blue Velvet Nudibranch should be acclimated using the Drip Method. It can be harmed by pump intakes and drains, so care should be taken to screen these off. It is sensitive to high levels of nitrate and will not tolerate copper-based medications.

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