Paradise Threadfin. One of my all-time favourites. I’ve been lucky enough to see one of these in person, long before I got into the hobby (though not the one featured in the video). This is an extremely rare, extremely delicate fish, and not one suited for the general hobby.
They grow large (10”), need to be kept in groups for long-term health, require a soft substrate, hiding places (but nothing that could damage their barbels/filaments), pristine water, live food for the first few weeks and may well need brackish conditions on top of this, as they’re euryhaline. The tank would need to be custom-built, ensuring that the length, as well as depth and height are more than enough for long-term care. It’s gotta be big.
All of this being said, these fish are incredible and need to be loved by all!
Paradise Threadfin
Genus: Polynemus
Species: P. paradiseus
See Below for Care Details
Maximum Size: 10”
Aggression: Low
Temperature: 75-82 F
pH: 8-8.5
Hardness: 15-25 dH
Brackish Tolerance: 1.000-1.025, best kept 1.005-1.025
Minimum Tank Size: 60 gallons
Feeding: Brine and Mysis shrimp, earthworm pieces, small pieces of fish and shellfish. Will likely need live foods at first
Notes: A euryhaline species, the Paradise Threadfin is most commonly found in strongly brackish or marine waters in the wild and return to freshwater to spawn. Though they can survive in freshwater that is extremely hard, this is a very delicate species even in the best of conditions. Thus it is better kept with at least some level of salt added in.
Paradise Threadfins are very active fish, swimming out in the open at all levels of the aquarium. They do not appear to be a social species, but may be kept in groups provided the tank is large enough and water quality is kept extremely clean. Aggression is not highly reported with these fish, though they will eat any tankmates they can fit in their mouths. These fish should be kept on fine sandy substrates and rough tank decor like lava rock should be avoided.
These fish need a great deal of care to do well. They do not ship well, are prone to being nipped by other fish due to their long, delicate fins, and commonly get bacterial infections where fins get damaged. Quarantining of new specimens to the tank is a must and prophylactic treatment with a suitable antibiotic is highly beneficial. Given this, they are best kept in singly species tanks, if at all. Not a fish for a beginner or intermediate fishkeeper.
Sources
The Paradise Threadfin, Practical Fishkeeping
Freshwater Picture of the Day Archive, Wetwebmedia
Origin: Eastern Indian Ocean and Western Pacific: west coast of India to Thailand. Probably occurs in Malaysia and Laos.
Water: This is a euryhaline species and enters freshwater. Those featured here were packed in freshwater and are kept in hard, alkaline freshwater.
Diet: Wild fish eat small shrimps and fishes. Captive specimens are tricky to feed initially. These needed live daphnia and brineshrimp to start, but now take frozen foods. They become hyperactive when food is added. Habitat: Sandy estuaries. Source:http://www.practicalfishkeeping.co.uk/features/articles/the-paradise-threadfin-polynemus-paradiseus Okay all, here's what I'm buying if I ever win the lottery.... lol
