Red bugs

Identification

Minute flea-like copepods about 0.5 mm long — barely visible to the naked eye and usually discovered in macro photographs. Under magnification they look yellow-gold with a distinct red dot or rear section. They crawl on Acropora tissue, favoring shaded areas under branches. First signs are faded or browned color, poor polyp extension and slow decline on smooth-skinned Acropora such as A. granulosa and A. lokani.

Often confused with

Black bugs and white bugs — other tiny Tegastidae-type copepods that look dark or pale grey instead of yellow with a red spot; magnification settles it. Also confused with AEFW (flat, gliding worms with bite marks and skeleton egg clusters — red bugs leave neither) and with harmless red planaria on rock and glass, which are far larger and flat.

What it targets

Acropora spp. only, per WetWebMedia and research summaries. They feed on coral tissue fluids / mucus and irritate polyps rather than eating skeleton.

How it spreads

Hitchhikes on Acropora frags and colonies from wild sources and other hobbyists, often unknowingly — many infestations are only spotted after frag trading. Research determined red bugs are live-bearers, so there is no long-lived egg bank, but untreated colonies keep reseeding the system.

Control (safest first)

Natural predation first for light infestations: dragonface pipefish perch on infested Acropora and methodically pick bugs off (LiveAquaria's documented solution), and some wrasses, gobies and filefish pick at them. No predator is a guaranteed eradication — pipefish are delicate, expert-level fish that need a mature tank full of micro-crustaceans. Bayer-type dips on removable frags knock bugs off individual pieces and suit quarantine, but dipping alone does not clear a display where colonies are encrusted and bugs remain on other Acropora. In-tank milbemycin oxime (Interceptor / Interceptor Plus, a prescription dog heartworm medication obtained through a veterinarian): the established whole-tank cure, usually run as repeat treatments about a week apart. NOT selective — it kills shrimp, crabs, amphipods and copepods, so remove ornamental crustaceans first, turn off carbon and skimming during treatment per the published protocols, and expect pod populations to need reseeding. Reefs.com's treatment summary lists one large-dog Interceptor Plus tablet (23 mg milbemycin) per 400 gallons of tank water, repeated at one week and again two weeks later. Blowing colonies off with a powerhead or baster several times a week is reported by some keepers to reduce numbers by dislodging bugs before they reattach; treat as suppression, not a cure, and do not trade frags from an infested system.

Natural predators

• Dragonface pipefish
• Melanurus wrasse→
• Six-line wrasse→

Field notes

A MARSH keeper who was dreading an Interceptor treatment found a pair of dragonface pipefish already eating frozen cyclops at a local shop; the female took to perching on the frag rack beside an infested teal stag, was seen picking items off it, and weeks later no red bugs could be found and the stag's polyp extension had visibly improved. Reef Sanctuary posters split the credit: pipefish fans called them wonderful for control, while others cautioned that even dragonface pipefish will not eradicate a full-blown infestation and only keep numbers in check once the population is knocked down — and one keeper who did run Interceptor reported losing shrimp and crabs but called the trade worth it. A UK keeper's blog account of getting Interceptor describes a three-step saga — educating the vet with internet printouts, bringing an infested branch in for microscope inspection to win the prescription, then importing the medication from the US — which matches why many keepers try predators and dips first.