Brackish fish that aren't

[nmonks]

In the new Aqualog brackish water book by Frank Schaefer, the author spends a fair number of words stating his case that things like glassfish, wrestling halfbeaks, and bumblebee gobies are not brackish water fish. According to the author (who collects fish from the wild), glassfish are never found in brackish water but only in soft, acidic conditions similar to those inhabited by discus! The hobby, of course, generally recommends that these fish should be kept in brackish water.

Apparently, bumblebee gobies and wrestling halfbeaks also come from fresh, not brackish, water.

For my own part, I have glassfish, bumblebee gobies, and three species of halfbeak in my own aquarium at home. Initially I planned on setting the tank up as a brackish system, but because I inherited a large royal panaque, I've gradually converted the tank from brackish and alkaline to being only moderately hard and slightly acidic (pH 6.5).

My bumblebee gobies and glassfish appear to be doing fine, and my halfbeaks are (apparently) producing regular broods of healthy fry. Admittedly, the halfbeaks producing the fry are Nomorhamphus spp. and not the Dermogenys sp (which are all females). But at least one of those halfbeaks is Nomorhamphis ebrardtii, a species supposedly from neutral to brackish rather than soft water.

Interestingly, the only time I lost any glassfish was when the tank was brackish; since converting to acidic conditions the glassfish have been completely healthy and in fact rather more strongly marked with black lines and spots. They certainly aren't shy or backwards at feeding time.

Among the other fish, both the platies and the black mollies seem fine, and the 'freshwater' sole, which I didn't think would like acidic water, is growing and seemingly doing well. It's been in the tank 6 months now, which is a good deal longer than most survive in community tanks, but nonetheless I'm still watching for potential problems. Like CFC and others here, by default I'd recommend people keep freshwater flatfish of any kind in alkaline to brackish conditions. Certainly the most common species, the hogchoker sole, probalbly demands brackish water over the long term. My freshwater sole came in under the "panoides" name, but it isn't that species, and it's possible I was lucky and got one of the (not all that numerous) species fully adapted to fresh water like Brachirus harmandi.

In short, my experience has been completely the reverse of what I'd expected.

My question is whether other people have similar or different experiences of these fish. We all know that there are lots of species described as "freshwater" but actually needing brackish/marine conditions (e.g. morays, most flounders, bullrouts, etc.). Are there fish described as brackish that aren't?

Anyway, just something to mull over this weekend,

Neale

 

[CFC]

Siamese tiger fishes (Datnoids/Couis sp) are often described as being brackish water fish and i have seen salinties up to 1.010 SG recomended for them but i have found that with the exception of Couis quadrifasciatus this is completely untrue. I attempted to keep my C.microlepis in brackish water but once the SG neared 1.005 the fish showed visable signs of distress with patches of its slime coat peeling off.

 

[penguinpimp1990]

ive kept glass fish in brackish tanks and theve been fine

 

[nmonks]

Texas cichlids will live and breed in seawater, but that doesn't make them brackish water fish.

The most commonly traded species is Parambassis siamensis. According to FishBase this fish comes from the middle Mekong, hundreds of miles from the sea. Similarly, Parambassis lala is said "to enter brackish water", implying that it is mostly found in freshwater.

On the other hand Parambassis ranga is said to occur in both without reservation, though the word "potamodromous" has nothing to do with brackish water and simply means it migrates up and down rivers and streams (e.g., with the rainy season).

The question is, I suppose, what's optimal for maintenance. I'm mindful of the figure-8 puffer, which is supposedly a freshwater fish but the overwhelming consensus seems to be that it does best in brackish water. Possibly glassfish are similar?

Cheers,

Neale

 

[CFC]

It has been my experience that bumble bee gobies, or at least the variety sold around here, always do better in brackish water. The first time i kept them i added them to a mature freshwater tank with a pH of around 7.8, they were lethargic and slowly faded away within a few months. The second time i kept them was in light brackish water with a SG of around 1.005 and pH of 8.2, they fared well and survived until i added a pair of knight gobies (Stigmatogobius) which promptly hunted them down and ate them all

 

[nmonks]

I agree with you about bumblebees, though I think there is some variation among species, and perhaps populations.

The other way of looking at this question is what species sold as brackish water fish invariably do better in freshwater. I'd start my list with kribensis, spiny eels, and the ropefish Erpetoichthys calabaricus. Some species of archer and Datnoides make the list too, and so do most halfbeaks.

I'm learning that some of the "freshwater" soles really do want freshwater, but given the difficulty in identifying them, I think the general advice to keep them at an SG of 1.005 is good. That won't harm a truly freshwater sole like Brachirus harmandi or Cynoglossus spp., but should be enough for the brackish water ones.

Cheers,

Neale

 

[Nethius]

I got 5 BB Gobies in Brackish water, and they are very active. I truely believe these to be brackish fish. I know of atleast 2 differnet fish labelled as bumblebee goby. Did the article mention a scientific name for the goby? If not who knows what fish he is actually talking about.

 

[SirMinion]

Figure eight puffers (Tetraodon biocellatus) are another species that is commonly found in freshwater, not brackish in the wild. They make feeding forays into brackish esturies, but spend most of their lives in freshwater.

However, there is overwhelming and long-term evidence that in the aquarium, this fish does considerably better, feeds better, resists disease better and lives longer if kept in mildly brackish water (around 1.005)

 

[nmonks]

The book includes words and pictures on at least half a dozen bumblebee goby species. There are actually rather more than that known in the genus Brachygobius, as well as Hypogymnogobius xanthozona. This latter, often called Brachygobius xanthozona by aquarists, is probably (almost certainly) never imported or traded. The commonly traded species (in the UK anyway) are Brachygobius sabanus and Brachygobius doriae.

Since the author is a collector as well as an aquarist, and this is an AquaLog book, I'm fairly happy to assume the names and pictures are correct. AquaLog books tend to have rock-solid systematics, whatever their other flaws.

Some species (e.g., B. doriae) are known to come from very soft, acid waters, and the author says that he has only ever found them in freshwater, not brackish. Though he also says that breeding is easiest (in aquaria, presumably) in brackish water. Mine are Brachygobius doriae I think, and are in slightly acidic, moderately hard water. I've seen one male in breeding colours, but as yet, no sign of fry.

I'm not suggesting that we all keep bumblebees in soft, acid water by the way, but it may be that at least some of our preconceptions are erroneous and worth thinking about. SirMinion's point about the figure-8 is bang on the nail here... while these fish 'should' be freshwater fish, they seem to do best in brackish aquaria. Do bumblebees fall into the same category? Are they freshwater fish that do best in brackish?

Cheers,

Neale

I got 5 BB Gobies in Brackish water, and they are very active. I truely believe these to be brackish fish. I know of atleast 2 differnet fish labelled as bumblebee goby. Did the article mention a scientific name for the goby? If not who knows what fish he is actually talking about.

 

[andywg]

I wuold also question the collection method.

I have not read the book, so cannot comment entirely (so may be very wrong) but conisder the salmon. This fish spends a lot of its time in the ocean and makes a foray into freshwater to breed. Put a rod in the stream and you'll catch them as they are more frequent. Put a rod in the sea and due to its size, you are not likely to catch them.

I wonder if the above (though not on such an extreme scale) could affect someone who is saying what sort of water a fish needs based on where they have seen them. I find it hard to believe that a fish would spend millions of years evolving to live in freshwater yet would live far better in an environment nothing like their own.

Just a thought.

 

[pica_nuttalli]

we need to pin this.

 

[simonas]

I agree with you about bumblebees, though I think there is some variation among species, and perhaps populations.

The other way of looking at this question is what species sold as brackish water fish invariably do better in freshwater. I'd start my list with kribensis, spiny eels, and the ropefish Erpetoichthys calabaricus. Some species of archer and Datnoides make the list too, and so do most halfbeaks.

I'm learning that some of the "freshwater" soles really do want freshwater, but given the difficulty in identifying them, I think the general advice to keep them at an SG of 1.005 is good. That won't harm a truly freshwater sole like Brachirus harmandi or Cynoglossus spp., but should be enough for the brackish water ones.

Cheers,

Neale

thats reassured me Neale!!! sorry just searching bout these fish, ow long did yours live for Neale and what siz did it grow to

 

[seffieuk]

thanks for bringing this old thread up to the top Simonas, it was an interesting read

Seffie x


ps also explains what happened to my BBg

 

[Eclecticoldsod]

Said it before, and I'll say it again: “if you want an argument, go brackish..!”
Only just getting into so-called 'brackish fish' after 50 years of purely freshwater, I am going to need 10 years of suck-it-and-see before I can offer any sort of opinion, but I can see why the subject is so difficult.
We divide water into three basic categories – marine, brackish, and fresh. Most 'life' – animal or vegetable – can only survive at one extreme or the other. These basic parameters are easy to work out. Brackish water – where fresh meets marine – is very different. It changes twice a day for a start, sometimes for miles up- or down-stream. There is no simple 'halfway' cut-off point with 'brackish'.
If I have learned one thing in all my years as a zoologist, it is that nearly all animals are chancers. They knew all about survival of the fittest long before Darwin put pen to paper.
OK, so you are purely freshwater, but once a day, half-a-mile downstream, the river suddenly starts tasting really nasty and salty – but is full of fresh tasty food. What do you do..? If you have any sense at all, you take a deep breath, zoom down there just long enough to feed your fat face, and then zoom back home again to digest it...
Many of your cousins living just 10 miles upstream know nothing about this daily largess and take no advantage of it. But the scientific world is ruled by the monkey people who named you, so you are now just a species... Quite often, the place you were first caught (or most commonly caught) is the place you are supposed to live.
(On that principle – should I to wish to breed humans – I'd capture a male and three females in Tesco, set up a small superstore, and let 'em get on with it... Sadly, they would probably breed like rabbits..!)
Far too many fish we keep today are still wild caught. The water they are most easily gathered from is not necessarily the best water in which to keep them. When we can go to a LFS and buy 'captive bred' fish and shrimps, we'll know in which conditions they truly belong...

 

[bitteraspects]

Siamese tiger fishes (Datnoids/Couis sp) are often described as being brackish water fish and i have seen salinties up to 1.010 SG recomended for them but i have found that with the exception of Couis quadrifasciatus this is completely untrue. I attempted to keep my C.microlepis in brackish water but once the SG neared 1.005 the fish showed visable signs of distress with patches of its slime coat peeling off.

The problem with this is that too many people group all datnoids in as "Siamese tigers". Only the pulchers are "Siamese tigers" and they are fresh water the only 2 datnoids found sometime in brackish conditions are the AT and NGT, and even these 2 are kept in full fresh water with no problems