#threadfin

References:

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

Polynemus paradiseus, Fish Profiles