algae

Dinoflagellates

A type of brown algae that forms snot-like patches with air bubbles. Difficult to eradicate and can be toxic to corals. Treatment: UV sterilizer, dosing, manual removal.

Symptoms

Brown or rust-coloured snot-like patches with trapped air bubbles on rock, sand, and coral bases (E1).
Slimy film that returns quickly after wiping and can irritate corals.
Potentially toxic to corals during heavy blooms (E1).

Common Causes

Blooms typically develop when competing organisms are disrupted or nutrients are very low or unstable.
Often follows tank disturbances — new sand/rock, heavy cleaning, or a recent crash.
Introduction through live rock or sand.

What to Check

Test phosphate and nitrate; very low or unstable levels often accompany dinoflagellate blooms.
Check flow and filtration — stagnant areas and poor water exchange favour the film.
Review the available control routes (E1: UV sterilizer, dosing, manual removal) — sources differ on the best sequence, so pick one approach and monitor.

What Not to Do

Do not wipe the film aggressively every day — repeated disturbance can prolong the bloom.
Do not add sensitive corals while an active bloom is present.

This guide is informational and does not replace professional veterinary advice. If fish are severely ill, consult a veterinarian.

Dinoflagellates

Symptoms

Common Causes

What to Check

What Not to Do

Cookie Preferences

Dinoflagellates

Symptoms

Common Causes

What to Check

What Not to Do