Sleepy Cod Oxyeleotris lineolata
Category: Aquatic Species
Sleepy cod (Oxyeleotris lineolatus) is a tropical species (need water over 22°C) native to tropical Australia. A related species, the Marbled Sand Goby (Oxyeleotris marmorata), is the highest priced freshwater fish in Asia, and a market for a similar fish exists in Australia's Asian sector, hence the interest in our cod.
Australia's sleepy cod is definitely excellent eating with high flesh recovery per Kg of fish and never has an off flavour so never needs any separate purging. Some argue that this fish has the best eating quality of all Australian freshwater fish and as such is much sort after to culture. It's grown in ponds and farm dams but it's much more suitable for growing in recirculating aquaculture systems (RAS) and aquaponic tanks. They are not a large fish, only reaching several Kgs in size so most suitable for tanks, if the water is hot and they have lots of food can grow very quickly.
The natural diet of sleepy cod is carnivorous; it has a natural diet of small fishes, shrimps, aquatic insects, and crustaceans. It's got a big mouth so can eat relatively big food. Its cannibalistic especially when small so be warned; if it gets hungry it can eat a neighbour. Two tailed fish are common when young and you can lose both as the larger can choke to death on the smaller.
Sorry, didnt have a two tailed sleepy cod photo, so you will have to make do with this Two Tailed Murray Cod photo.
To help avoid this they must be stocked at high densities and fed regularly. They go best on a high protein diet, most would just feed them a barramundi pellet. They are a quiet fish spending most of the day just lying around (hence the sleepy). That said they are creatures of habit so feed them regularly at the same time every day as they will be waiting and expecting a feed. Give them a big pellet as they have a big mouth. They tame relatively easily, and if you don't want to feed them pellets then they will eat live food such as other fish, worms, shrimps, yabbies etc., especially at night. They can also be fed frozen prawns, squid, yabbies and pilchards, just watch your water quality. Although they love pilchards there is a lot of oil, blood, small scales and flesh that ends up in the water column which that can create water quality problems.
It's a species that lives in creeks and stream of northern Australia. These streams flood and then dry into pools and this species is a survivor being tough and robust. It's a goby with fins that can be used to help it climb obstacles and in the wild will migrate upstream, climbing over obstacles or jumping up cascades and small waterfalls. That's a big problem for your aquaponic tank as these critters can easily jump out. They are tough and can survive extended periods on the floor but not recommended. Net your tanks so they can't jump out.
They are a tropical species preferring temperatures from 22°c - 28°c and pH range between 6.6 - 8. If your heaters fail then by 18°C these critters are in big trouble and eventually they just don't make it.
It you are in northern Australia then they will live and breed in farm dams. They are ambush predators and will take both lures and soft plastics being a fun fish to catch but not a lot of fight on the scheme of things. We also catch them in our redclaw traps when using fish as bait.
Fingerlings are available from time to time from a number of Queensland Hatcheries (just Google search or similar). Make sure you get weaned ones-check with the hatchery. They transport well in high densities. They are placid and easy to handle which is an attraction for many (ever handled fingerling eel tailed catfish-they are a handling nightmare-needle sharp spines). Rumour has it that females grow faster than males but I dont know how to tell the difference so I'm no help.
Although an excellent eating species, it's a tropical so you need very hot water. If I was going to that effort Id personally do Barramundi or Jade Perch (both when battered with chips and a side salad are excellent eating as well).