Olm

Proteus anguinus

The "human fish" of Slovenian caves: blind, pale pink and able to go years without eating. Some live for more than a century. Needs a chiller.

A peaceful freshwater amphibian that grows to 25 cm, lives near the bottom and needs 8–12 °C, pH 7.0–8.0 and an aquarium of at least 80 L.

Care at a glance

Water

Freshwater

Temperature

8–12 °C (46–54 °F)

pH

7.0–8.0

Adult size

25 cm (10 in)

Aquarium

80 L or bigger (21 US gal)

Temperament

Peaceful

Group size

Fine on its own

Swims

Bottom

Diet

Carnivore

Wild home

Flooded caves of the Dinaric Alps

Good to know

• Delicate. Sensitive to poor water quality.
• Bottom crawler. Walks along the substrate.
• Shy. Stressed without plants, rocks or caves to hide in.
• Eats invertebrates. Hunts shrimp, snails and crabs.

Tank mates

Few species share its water and stay safe with it: it is best kept with its own kind.

Will eat: Amano Shrimp, Celestial Pearl Danio, Chili Rasbora, Crystal Red Shrimp, Ember Tetra, Endler's Livebearer, Ghost Shrimp, Mystery Snail, Neocaridina Shrimp, Nerite Snail, Pea Puffer.

Eaten by: Asian Arowana.

Attacked by: Flowerhorn, Jack Dempsey.

Eats the newborn fry of: Angelfish, Betta, Black Skirt Tetra, Bloodfin Tetra, Boesemani Rainbowfish, Cardinal Tetra, Cherry Barb, Cockatoo Dwarf Cichlid, Congo Tetra, Corydoras, Demasoni Cichlid, Discus and 25 more.

Colours

• Cave White mythic
• Black Olm mythic

The care values are the ones Aquarius uses, based on how these animals live. Tank mates follow the game's rules: water type, temperature and pH, who can swallow whom, fin nipping, temperament and territory.