TankBud

Rainbow sicyopus

Sicyopus auxilimentus

Also known as Auxilimentus goby, Rainbow goby

FreshwaterFish

Rainbow sicyopus (Sicyopus auxilimentus)

Care at a glance

Temperature
73–81°F
23–27°C
pH
6.5–7.8
Adult size
1.4 in
3.5 cm
Minimum tank
14 gal
54 L
Temperament
Peaceful
Social behavior
Social
Swim level
Bottom
Diet
Carnivore
Difficulty
Difficult
Breeding
No record
Rarity
Rare
Family
Oxudercidae
Origin
Philippine and Sulawesi streams

Overview

The rainbow sicyopus is a tiny, gentle stream goby for a fast tank with steady current. It is a difficult fish for experienced keepers.

Did you know

The rainbow sicyopus wears the colors of the algae-grazing gobies, but it earns its living as a tiny hunter of small invertebrates.

Caring for the rainbow sicyopus

Keep the rainbow sicyopus in a small group, in a well-oxygenated tank of at least 14 gal (54 L) with steady current. A powerhead gives strong flow, and rounded stones, cobbles and boulders give perches and cover. Change the water often to keep it very clean, and fit a tight lid, since these gobies climb.

Hold the water at 73 to 81°F (23 to 27°C), with a pH of 6.5 to 7.8, from slightly acidic to slightly alkaline. It is a tiny carnivore, so feed it as a micro-predator rather than expecting it to graze. It stays low in the current and takes small meaty foods drifted into the flow. Offer frozen and live cyclops, baby brine shrimp and finely chopped bloodworm.

The rainbow sicyopus is gentle and sociable. Give males room to hold a stone and display their colors. Keep only calm, small tank mates that will not out-compete it for these fine foods. Rainbow sicyopus larvae develop at sea, and the species has no aquarium breeding record.

Good to know

Sicyopus auxilimentus is a member of the family Oxudercidae. Watson and Kottelat described it in 1994 from a single creek on Leyte in the Philippines. That same stream produced several other rare gobies. It is also known as the auxilimentus goby.

In the wild

In the wild, the rainbow sicyopus lives in clear, fast island streams in the Philippines. It holds to rock and cobble in warm, oxygen-rich water swept by current.

Weekly picks

Tank mates

The rainbow sicyopus is a peaceful, social species that keeps to the bottom. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does a rainbow sicyopus need?

A rainbow sicyopus needs at least 14 gal (54 L). It spends most of its time in the bottom.

What temperature and pH does a rainbow sicyopus need?

A rainbow sicyopus is comfortable at 73–81°F (23–27°C) with a pH of 6.5–7.8.

What does a rainbow sicyopus eat?

A rainbow sicyopus is a tiny carnivore that takes small meaty foods rather than grazing. Offer frozen and live cyclops, baby brine shrimp and finely chopped bloodworm, drifted into the flow.

How big does a rainbow sicyopus get?

An adult rainbow sicyopus reaches about 1.4 in (3.5 cm).

How does a rainbow sicyopus breed?

Rainbow sicyopus larvae develop at sea. The species has no aquarium breeding record.

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