4 Puffers Dead

[crazedpuffer]

Sharks are sometimes found in brackish - nearly fresh conditions while searching for food, does that make them not 100% Marine fish?
It's not like they're living there, they are trying to get to a new body of water and/or geting food.

[Pufferpunk]

LOL, I visit other contries but I'm still an American.

Since it spends most of it's life in FW. only visiting BW occasionally & since we have to choose what is best for the long-term survival of each species, it is best kept in the water it is most comfortable in.

[Fella]

LOL, I visit other contries but I'm still an American.

Since it spends most of it's life in FW. only visiting BW occasionally & since we have to choose what is best for the long-term survival of each species, it is best kept in the water it is most comfortable in.

I didn't say anyone should be kept in brackish in captivity (not that I think it would do much harm below 1.005 like any freshwater puffer, but save that for discussion for a rainy day.).

http://www.fishbase.org/Summary/species ... e=lineatus

While I'm not saying it is better to keep in brackish in captivity (who would know? I doubt it's ever been tried for a reasonable amount of time), Fishbase states that Tetraodon lineatus is not a 100% freshwater fish, and is found in brackish regions as well.

Nowhere have I said anyone should keep it in brackish or otherwise. The point is, a fish is not 100% freshwater if it is found occasionally in brackish water in the wild. All I have said is that it is occasionally found in brackish in the wild according to fishbase, meaning by definition it could not be considered a "100%" freshwater fish.

[Myaj]

I suppose its more of a "people keeping this species have found it does best long term if kept in freshwater only, so it is recommended to be kept in a 100% freshwater environment".

Better?

[Fella]

I suppose its more of a "people keeping this species have found it does best long term if kept in freshwater only, so it is recommended to be kept in a 100% freshwater environment".

Better?

i still think there is some element of misunderstanding here. I keep my fahaka in freshwater. I would not keep it in freshwater if I did not think that was the best condition to house it in. I am not recommending anyone to keep T. lineatus in brackish water.

Since it spends most of it's life in FW. only visiting BW occasionally & since we have to choose what is best for the long-term survival of each species, it is best kept in the water it is most comfortable in.

But couldn't this be said for figure 8 puffers as well? In the wild they are a freshwater species only. Again, i'm not saying everyone should keep their F8's in freshwater, but saying that no one seems to have conducted a fair test on their fahaka to say whether or not it would do better in brackish water over the long term. Perhaps it would lengthen the lifespan by decreasing the toxicity of nitrate? maybe it would help fend off against illness? Who can say. All I am stating is that there is still a lot to be learned about puffers, and perhaps we would need more 15 year+ long studies into what would work out best for our fish.

[Myaj]

No one is discouraging anyone from doing long term studies... but we want to give the information that we know, so far, to be the information that provides the best possible outcome.

Future discoveries may prove that wrong, or that other methods work just as well. But until someone does those studies, we just have to work with what we know DOES give the fish a good full and healthy life.

The problem is, not many people are set up to do long term studies on fish like Fahakas. You'd need several specimens, at 120+ gallons per, and a good 10+ years to dedicate to the study. Well, maybe not, maybe at the 1 year or 5 year mark there might be significant health problems or growth differences.. but then again, they might have the exact same (or comparible at least) outcomes.

So yes, there is more studying to be done, more to be learned. But that doesn't mean we shouldn't give out the best "known" information. If someone wants to experiment, they should be taking the time to educate themselves and prepare for the undertaking.. its not something the casual fishkeeper would be trying to do, and for the most part, the information here is for the casual fishkeeper, basic care info.

[Hilly]

I dont think Fella was implying in any way that this fish should be kept in captivity in brackish, merely that in the wild with the distribution these puffers have that they do occur in the wild in brackish water. Without a long term study or visiting their natural habitats for a long term observation there is no way we can tell if there is any difference to keeping them in brackish or freshwater or what even the salinities are or how long they stay in brackish areas. Predators go where the food is and if there is a plentiful supply of food in a brackish area it's not impossible to think that a Fahaka may stay in that area for a very long time while the going is good.

But keeping them in a tank it's best to stick to freshwater as that is to the best of peoples knowledge, the thing to do, which i dont think was ever in question.

[Myaj]

Right, I know he wasn't saying that, just explaining the reasoning behind why we say freshwater is best as far as we know.

[nmonks]

Fella is right on the money here. By definition almost, brackish water fish are visitors. They are either passing through between spawning and feeding grounds (e.g., eels, salmon) or move in and out while foraging for food (e.g., porgies, snook).

There is absolutely NO sense dividing fish into "freshwater" and "marine" species and placing a brick wall between them. Nature doesn't work that way. All freshwater fish have some degree of tolerance for salt, and all marine fish have some degree of tolerance for freshwater. Ignoring this critical fact gives rise to these nonsense myths like "catfish are allergic to salt" (when there are not only plenty of freshwater catfish that enter brackish water but also at least five families with examples found in high-end brackish waters and the sea: Ariidae, Aspredinidae, Bagridae, Pangasiidae, and Plotosidae). Understanding that fish are able to adapt to different salinity environments explains why you find freshwater fish (like roach) living alongside marine fish (like flounders) in the Thames Estuary.

While many fish are able to tolerate movements between freshwater and the sea without coming to any harm, they may not be able to breed in both environments. Eels have to breed in the sea, and salmon have to breed in freshwater. On the other hand, a LOT of marine fish breed in estuaries, including numerous marine puffers. Among fisheries scientists, estuaries and mangroves are called "the nurseries of the sea". The importance of brackish water as a habitat for juvenile fish cannot be overstated.

Pufferfish as a group are tolerant of salinity variations. Out of about 120 known marine pufferfish, there are something like 40 marine pufferfish that regularly enter brackish and fresh waters. Of the 30 or so species considered "freshwater puffers" or "brackish water puffers" there's no hard line between the freshwater and the brackish water ones. Many of the "freshwater puffers" have a high tolerance for salt and inhabit brackish water in parts of their range: Colomesus asellus, Tetraodon mbu, Tetraodon cutcutia, Tetraodon leiurus, Tetraodon lineatus, and Tetraodon pustulatus among them. Conversely, many of the so-called brackish water puffers are commonly (perhaps normally) found in freshwater rivers across most of their range, as with Colomesus psittacus, Tetraodon biocellatus, Tetraodon fluviatilis and so on.

Normally what prevents brackish water fish from holding onto a completely freshwater niche is nothing to do with them getting sick under freshwater conditions, but competition from true freshwater specialists. Think of it this way: a brackish water fish has to spend energy maintaining two sets of hardware, one for the sea, and one for freshwater. It's a jack of all trades but master of none. Compared with its freshwater rivals, it can channel less energy into reproduction, growth, immunity, etc. In other words, its freshwater rivals grow faster and breed quicker, so can grab more "ecological space". A good example of this is Sarotherodon melanotheron, a tilapia from West Africa. In freshwater aquaria, it does perfectly well; indeed, it is normally sold as freshwater aquarium fish. But in the wild, it's almost never found in freshwater. Seemingly, competition from true freshwater tilapia wedges it into the brackish water niche. In other words, what prevents a brackish water fish being a success in freshwater conditions may not be relevant to aquarium situations. So the absence of a brackish water from freshwater habitats doesn't mean freshwater conditions are lethal directly, but merely not optimal when factored into breeding success and growth rate.

Anyway, if this doesn't fit into your neat mental picture of one box for freshwater pufferfish, and another box for brackish water pufferfish -- don't get cross with me, take it up with Mother Nature!

Cheers, Neale

Just because a fish "visits" BW occasionally, doesn't make it a BW fish.

But if it is found in brackish water in the wild then it is not a 100% freshwater fish.

[Myaj]

All very true.

But if we are talking about the best way to take care of one in the home aquarium, where you simply can't provide varying salinities without crashing your biofilter or create a system where the fish can choose which salinity it wants to be in... we have to pick a single type of water that the species does well in, long term. Correct?

[nmonks]

Yes and no. You can vary the salinity in a brackish water tank (within limits) and the bacteria will adapt sufficiently quickly that there's no harm done. For example, you can have a tank and constantly vary the SG between the range 1 and 1.005 with each water change, and the fish and filter will be happy. In lab conditions, using "mesocosm" aquaria, you can even vary the salinity more dramatically than this, and have perfect water quality (see: 'Dynamic Aquaria').

Do I recommend people do this? Only within tight margins. If you overdo the SG changes, you do run the risk of harming the filter bacteria. For example, going from SG 1 to SG 1.012 in one fell swoop is probably a bad idea. But 1 to 1.002 in one water change shouldn't cause any problems.

There's some evidence with "difficult to breed" species like scats and monos that varying the salinity helps. I dare say the ideal conditions for both figure-8s and GSPs would be a varying salinity regime. But since I've not kept either species, I hesitate to give that as general advice. As you say, picking a good "happy medium" is probably safest.

I doubt (say) Tetraodon lineatus swims between fresh and brackish water. It's too sluggish and vulnerable to predation. Far more likely that the ones in brackish water stay put, for their entire lives. Is it ideal for them? Perhaps not; but that quality of "ideal-ness" may be more about being able to breed and compete than actually being physiologically stressed. They may even do very well. Puffers are a marine group that have only recently invaded freshwater habitats; by default, you would expect them to have a very high tolerance for salt.

Cheers, Neale

All very true.

But if we are talking about the best way to take care of one in the home aquarium, where you simply can't provide varying salinities without crashing your biofilter or create a system where the fish can choose which salinity it wants to be in... we have to pick a single type of water that the species does well in, long term. Correct?

[julesee]

I love when someone actually posts an educated reply to a thread, rather than an arrogant and useless one sentence reply. Thanks Neale, you really are a great addition to this forum!

[Nick]

I intentionally rotate my GSP SG in the entire protein skimmer/LR acceptable range, from 1.018 to 1.026, then back down again, at a bit under 1.002 per week. It doesn't seem to bother my mushroom coral or change how much skimming gets done by my pathetic seaclown.

[Pufferpunk]

I love when someone actually posts an educated reply to a thread, rather than an arrogant and useless one sentence reply. Thanks Neale, you really are a great addition to this forum!

Although I don't see any arrogant or useless replies on this thread, I too appreciate Neale taking his valuable time to post at TPF.

[Myaj]

You can vary the salinity in a brackish water tank (within limits) and the bacteria will adapt sufficiently quickly that there's no harm done. For example, you can have a tank and constantly vary the SG between the range 1 and 1.005 with each water change, and the fish and filter will be happy.

But that goes against all the teachings here about not changing your salinity more than .002 each week.

You certainly can move your puffer gradually back and forth, but I personally don't feel comfortable recommending bigger jumps that might crash the biofilter. Again, most of the info here is for people new to puffers that haven't studied advanced techniques and things of that sort.

Maybe I'm just confused though as to what this discussion is about. I'm under the impression its about what to recommend to someone new to puffers keeping a certain species. If its a discussion about advanced testing on the benefits of varying salinities, etc, by all means, valid points.