I've been a huge fan of brackish species for many years now, had a tank about 15 years ago and would love to do another some day. I do have a question I've always wondered about. Most people ask which freshwater species can tolerate brackish conditions, low to moderate usually. But I've always wondered are there any fish commonly sold as saltwater species that can be acclimated down to a brackish level and actually survive there for extended periods of time? I'm talking about a salinity of around 1.010-1.015. I'd just be curious if it's possible.
There are two answers here - a general and a specific. From a general standpoint, I think many marine fish possibly have more tolerance for hyposalinity than we give credit for. At least one significant, well respected author and aquarist, Lance Ichinotsubo, states he keeps his fish only marine tanks at 1.010 over the long term with great results. I couldn't say myself how effective or ethical this is but I imagine it's an topic that is vastly underexplored.
Specifically, there are a good handful of marine species that can tolerate this range. Of course there are the brackish water staples like Scats, Monos, Tete Sea/Silver Shark Catfish, and any number of flounders/soles, killifish, and livebearers that make their way into full salinity for long stretches of time. But there are also several Puffer species, not to mention Needlefish, a few Stonefish, Lionfish, Zebra and Peacock Bennies, Batfish/Spadefish (Platax spp being well known), Stripies, Barramundis, several Snapper species, Sergeant Majors, and a few Waspfish. And these are only the species that appear in the aquarium trade! I suspect several hundred species can make that transition.
Gonna remake my wof seawing/skywing ocs (Pietersite and Waspfish) and give one a sanding gf (Tarantula) who’s kidnapped a wandering assassin scavenger who could very much kill her and escape but is staying out of curiosity (Vincent. It’s Vincent again I love putting her in situations)
“Found singly or in pairs rocking in the current during the day over sand, rubble and weed bottoms of shallow reefs. They feed nocturnally on tiny crustaceans by ambushing their prey pretending to be a dead leaf.” (Source)
This pair of Cockatoo waspfishes we see frequently in the shallow water in front of our dive center. On this picture they are easy to identify as fishes, but in reality it is much more difficult. While laying in wait for small shrimp and crabs to feed on, they let them selves drift with the water movement, mimicking a dead leaf or a piece of seaweed. They prefer dusk and darkness so we spot them mostly during afternoon and nightdives. #lumbalumbadivingmanado #bunaken #housereef #wonderfullindonesia #northsulawesi #underwaterphotos #waspfish #cockatoowaspfish #holliday #snorkeling #scuba #nightdive #scubadiving #duiken #dyk#tauchen #plongee #diveholiday #diving #marinelife (at Lumbalumba Diving - Manado) https://www.instagram.com/p/CIuFth3hnKh/?igshid=1szm2txvek4b1
The Whiteface waspfish, is a species of waspfish reaching about 4 inches in length native to reefs of the Indian Ocean and the western Pacific Ocean. This fish inhabits silty coastal reefs and sheltered sand habitats in coastal bays and deep offshore. The whiteface waspfish is nocturnal, coming out at dusk, and usually buries itself in the sand during the day. It is uncommon and mainly known from prawn trawling grounds.