Max Size: 5.5cm

Red Line Lizard Tetra (Iguanodectes geisleri)

The Red Line Lizard Tetras are a scarce, peaceful, enjoyable, medium-sized freshwater fish that grows up to 9cm long. They are slow-moving and appear to swim against the current in slow motion. Their slim bodies seem to wiggle as they swim against the current of the water. They will offer an excellent addition to a community aquarium.

Red Line Lizard Tetras have three longitudinal bands on the flank starting at the end of the operculum, 1 is a red-pink colour, the other is a yellowish colour, and the other is a dark almost black, decreasing and ending below the adipose fin. They also have two red spots in the caudal peduncle over a large black patch, both of which extend halfway into the caudal fin. Their dorsal, pectoral, pelvic, caudal and anal have an intense yellow-gold colour that fades out towards the ends of the fins. Their body colours seem to change a lot, from a light beige to a bright green.


Red Line Lizard Tetra
Red Line Lizard Tetra
Quick Facts
Scientific NameIguanodectes geisleri
Other NamesThree-banded lizard tetra
OriginsBrazil, Venezuela
Aquarium LevelMiddle - Top
Best kept asGroups 6+
Lifespan5 - 6 years
Water Parameters
Water TypeFreshwater
PH5 - 7
GH2 - 10
73 - 80℉
22.8 - 26.7℃

Natural Habitat

Rio Negro


In the home aquarium, the Red Line Lizard Tetra will readily accept most good quality dried foods such as granules, flakes and sinking pellets. These modern food products have been developed to provide all adequate nutrition to maintain your fish's health and dietary requirements.

Providing additional foodstuffs such as live, frozen, and freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week will provide additional benefits to your fish's health and well-being but is not a must for this fish.

It should be noted that bloodworms should only be given as an occasional treat and should not be used as the staple diet as they are difficult for fish to digest and can potentially cause blockages.

This fish is an omnivore in the wild, meaning it will consume some vegetable matter. Although most modern fish foods take this into account and include them in their products, you can still supplement your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini. Ensure you do not overfeed your fish and remove any leftovers the following day.

Sexual Dimorphism

It is relatively easy to determine males from females. Adult males can be easily recognised as they display red markings in the pectoral, pelvic, caudal and anal fins which are lacking in females.

Other Tetras of interest

Adonis Tetra(Lepidarchus adonis)
African Moon Tetra(Bathyaethiops caudomaculatus)
African Red Eyed Tetra(Arnoldichthys spilopterus)
Arowana Tetra(Gnathocharax steindachneri)
Black Darter Tetra(Poecilocharax weitzmani)
Black Line Tetra(Hyphessobrycon scholzei)
View all Tetras
Date Added: 31/08/2020 - Updated: 02/12/2021 17:35:47