Care library / Health

Health guide, not a diagnosis · Serious if left

Hole in the head (HLLE)

Also called head and lateral line erosion, HLLE, HLLES, hole-in-the-head, lateral line depigmentation (LLD), chronic ulcerative dermatopathy

Facts checked against sources on 16 Oct 2026. See sources

Signs

Pits or erosions in the skin over the sensory pores of the head and along the lateral line
Lesions can join up into larger eroded areas; loss of pigment along the lateral line

Cause

Cause not settled; best treated as a sign of poor conditions rather than one disease. Linked factors with evidence: full-stream activated carbon (shown experimentally in a marine surgeonfish), the intestinal flagellate Spironucleus vortens (found in head lesions of discus and angelfish), chronic nutritional stress (catfish model) and water source/quality. Seen in cichlids such as discus.

What to do

Remove the cause: move the fish or change the system/water conditions and stop full-stream activated carbon; give supportive care and antimicrobials only when warranted. Metronidazole is the treatment for confirmed Spironucleus (ornamental fish only, not food fish). Vets have also used topical becaplermin gel.

If a fish is badly ill, talk to an aquatic vet.

Prevention

Keep good, stable environmental conditions (water source and quality, no full-stream activated carbon); for groups of fish, prevention is about fixing suboptimal environmental and physiological conditions.

Medicines used for it

Always read the label first

MetronidazoleParasite treatments

Seachem FocusAntibacterial

eSHa HexaMitaDewormers

Praziquantel (generic)Dewormers

Quarantine protocol kitQuarantine protocols

Sources

5 facts checked with sources

Species often affected

183 species

AngelfishPterophyllum scalare

Easy15 cm24–30 °C

DiscusSymphysodon aequifasciatus

Moderate13.7 cm26–30 °C

OscarAstronotus ocellatus

Moderate45.7 cm22–27 °C

German blue ramMikrogeophagus ramirezi

Moderate4.2 cm27–30 °C

Bolivian ramMikrogeophagus altispinosus

Moderate8 cm24–28 °C

Cockatoo dwarf cichlidApistogramma cacatuoides

Moderate7.5 cm24–28 °C

KribensisPelvicachromis pulcher

Easy10 cm24–27 °C

Convict cichlidAmatitlania nigrofasciata

Moderate10 cm24–28 °C

Jack DempseyRocio octofasciata

Moderate25 cm22–28 °C

Firemouth cichlidThorichthys meeki

Moderate17 cm24–28 °C

SeverumHeros efasciatus

Moderate20 cm22–29 °C

Green terrorAndinoacara rivulatus

Moderate20 cm20–24 °C

Electric blue acaraAndinoacara pulcher

Easy15 cm22–28 °C

Silver arowanaOsteoglossum bicirrhosum

Hard90 cm24–30 °C

Alligator garAtractosteus spatula

Spotted garLepisosteus oculatus

Rainbow snakeheadChanna bleheri

Easy17 cm14–28 °C

Red-bellied pacuPiaractus brachypomus

Hard88 cm23–28 °C

Senegal bichirPolypterus senegalus

Moderate50 cm24–28 °C

RopefishErpetoichthys calabaricus

Moderate40 cm24–28 °C

Elephantnose fishGnathonemus petersii

Hard23 cm24–28 °C

African butterflyfishPantodon buchholzi

Moderate12 cm24–30 °C

Marbled hatchetfishCarnegiella strigata

Easy3.5 cm24–28 °C

PencilfishNannostomus beckfordi

Moderate6.5 cm21–27 °C

Pea pufferCarinotetraodon travancoricus

Moderate3 cm24–28 °C

Bumblebee gobyBrachygobius doriae

Moderate3.5 cm24–28 °C

Indian glassfishChanda ranga

Easy8 cm22–28 °C

Lyretail killifishAphyosemion australe

Easy6 cm21–24 °C

Clown knifefishChitala ornata

Hard100 cm24–28 °C

Black ghost knifefishApteronotus albifrons

Moderate50 cm24–28 °C

Peacock eelMacrognathus siamensis

Moderate30 cm24–28 °C

Agassiz's dwarf cichlidApistogramma agassizii

Moderate7.5 cm23–28 °C

Yellow dwarf cichlidApistogramma borellii

Easy6.5 cm20–26 °C

Three-striped dwarf cichlidApistogramma trifasciata

Moderate5.5 cm20–25 °C

MacMaster's dwarf cichlidApistogramma macmasteri

Moderate5.5 cm24–28 °C

Hongslo's dwarf cichlidApistogramma hongsloi

Hard6 cm24–28 °C

Banded dwarf cichlidApistogramma bitaeniata

Moderate7.5 cm24–28 °C

Panda dwarf cichlidApistogramma nijsseni

Hard3.9 cm24–28 °C

Viejita dwarf cichlidApistogramma viejita

Moderate23–28 °C

Panduro dwarf cichlidApistogramma panduro

Moderate7 cm24–28 °C

Inka dwarf cichlidApistogramma baenschi

Moderate5.5 cm20–26 °C

Steindachner's dwarf cichlidApistogramma steindachneri

Moderate8 cm20–25 °C

Diplotaenia dwarf cichlidApistogramma diplotaenia

Moderate3 cm24–28 °C

Juruá dwarf cichlidApistogramma juruensis

Moderate2.4 cm24–28 °C

Pucallpa dwarf cichlidApistogrammoides pucallpaensis

Moderate4 cm22–27 °C

Checkerboard cichlidDicrossus filamentosus

Hard3.8 cm27–30 °C

Spotted dwarf cichlidCrenicara punctulata

Easy12 cm23–27 °C

Golden dwarf cichlidNannacara anomala

Easy7.6 cm22–26 °C

Sheepshead acaraLaetacara curviceps

Easy8 cm22–28 °C

Red-breasted acaraLaetacara dorsigera

Easy8 cm22–28 °C

Sunset dwarf cichlidTaeniacara candidi

Hard5 cm27–30 °C

Cupid cichlidBiotodoma cupido

Moderate12 cm24–28 °C

Altifrons eartheaterGeophagus altifrons

Moderate25 cm26–30 °C

Red hump eartheaterGeophagus steindachneri

Moderate20 cm24–28 °C

Redstriped eartheaterGeophagus surinamensis

Moderate25 cm22–25 °C

Pearl cichlidGeophagus brasiliensis

Moderate28 cm18–26 °C

Tapajos red head eartheaterGeophagus pyrocephalus

Moderate25 cm26–30 °C

Threadfin eartheaterSatanoperca daemon

Hard25 cm24–28 °C

Demon eartheaterSatanoperca jurupari

Hard25 cm20–28 °C

Paraguay eartheaterGymnogeophagus balzanii

Moderate20 cm21–25 °C