Prehistoric monster fish

Prehistoric monster fish, Thalassophryne amazonica

The oddly-named Prehistoric monster fish is a venomous batrachoidid from South America. Matt Clarke explains how to keep and breed it.

Common name: Prehistoric monster fish

Scientific name: Thalassophryne amazonica


Pronounced: Tha-lass-oh-fry-nee amazon-eye-ka

Origin: Peru, Brazil and Ecuador; Rio Conambo, Corriantes and Shiona.

Size: 10-15cm/4-6"

Price: �8-12

Water: Seems to be quite adaptable. Can be kept in both soft, acidic water and slightly hard, alkaline water. Salt is not necessary.


Diet: Fish or shrimps, preferably frozen. Some fishkeepers claim that the species is reluctant to accept anything other than live fishes. Live river shrimp is well worth a try.

Temperament: Very shy and retiring. Will spend most of the day submerged beneath the sand. Fiercely predatory and will consume any smaller fishes that pass overhead.

Stocking: Can be kept in groups.

Aquarium: The aquarium must have a deep sandy substrate to allow the fish to burrow. A 5-8cm/2-3" layer of silver sand is ideal. The species is inactive so a large tank is not necessary. An adult pair can be easily kept in a 61cm/24" aquarium.

Sexing: No external sexual differences are known but the sexually mature females are much larger than males. Difficult to spot other differences due to the burrowing behaviour of this species.


Breeding: A small number of large (7mm) amber eggs are laid over a three to four-day period. The eggs are non-adhesive and have a large semi-adhesive filament on the underside. Most eggs are buried within the sand, a small number are scattered upon the substrate. For more details on breeding this species check out my other article on monster fish.

Notes: This weird nocturnal oddball isn't often seen above the sand - you may just see its eyes sticking out

of the substrate. The spines may be venomous - handle with care. It's a member of the family Batrachoididae, commonly known as toadfishes or batrachoidids (pronounced bat-ra-koy-dids, not bat-ra-koids).

Identification: This species was originally traded as Daector sp. and was misidentified in an Aqualog guidebook. Back in 2002, before the species was known by fishkeepers, I contacted batrachoidid taxonomist Dr Bruce Collette who first confirmed the true identity of the fish as T. amazonica. PFK was the first to publish the true identity of this species. It is also being sold under the name Potamobatrachun tripinosus by suppliers in Peru.


Related species: There are at least five other species in the Thalassophryne genus, including: Thalassophryne nattereri (found in the western Atlantic); Thalassophryne maculosa (found in the western central Atlantic); Thalassophryne megalops (from the Gulf of Panama); Thalassophryne montevidensis (from the south Atlantic around Montevideo) and Thalassophryne punctata (from the south west Atlantic). As far as I am aware, T. amazonica, is the only true freshwater species.

Alternatives: The Toadfish, Allenbatrachus grunniens, is similar in appearance. This species benefits from some salt in the water.

Price: Prices can range from under a tenner to �30 or �40 depending on the supplier.


source :www.practicalfishkeeping.co.uk