Why are Figure 8's brackish?

[bigpuff]

They are freshwater in the wild but this website (among others) claims that they live longer and have stronger immune systems in brackish water. I work in research and I'm a little skeptical of this claim; I'm not saying it's wrong, I just want to hear the reasoning/evidence behind it.

They are primarily freshwater in the wild which would make it surprising if their bodies were somehow better suited to brackish water. Evolutionarily speaking, that seems unlikely. I'm worried that the claims of them living longer and being healthier have originated from one persons anecdotal evidence and was subsequently accepted as fact by the internet world (ie. I had this puffer in fresh and this one in brackish, and the brackish one lived longer so it must be because of the brackish water - this evidence isn't reliable). Can someone clear this up for me?

[TheStig]

Evolutionary speaking, salmon has been able to hatch in FW, eventually move to marine, and then when ready to spawn, transition back to FW.

Since scientific studies on these puffers are minimal, and info usually regurgitated from site to site, my guess is while they are found in FW in the wild, they also have a choice to migrate to low brackish and may do it frequently... back n forth, back n forth. But w/o tagging them and following their movements, and logging their migration, we can't really know for sure. But we can base on the experience of long-time puffer keepers to help us in aquaria. Of course, we are all always learning, regardless of how long we have been in a hobby or sport.

I will say that, growing up in SE Asia, where the F8s originate, we have a lot of estuaries... so there may be as many F8s found in FW as there are hanging in low brackish... it's a fine line btw the 2, ya know.

Good discussion topic.

[Pufferpunk]

Yes, they may be in FW in the wild but very HARD water. The easiest way to keep the water stable at the parameters required for this hard water fish is to add salt.

[bigpuff]

So, it's more likely that how hard the water is and not how saline the water is, is the reason they are reported to do better in brackish?

[Pufferpunk]

Yes

[bigpuff]

So, what kind of GH and KH should I be aiming for?

[Pufferpunk]

It really is impossible to keep a stable GH/KH, if that's what you're thinking. I really wish I could contact RTR about this for a better explanation. I'm just going by what he has posted on this subject the past. It's all on this site somewhere. Unfortunately, he went blind before he wrote his F8 article, which was supposed to be on his 20 years of research for this species.

[Pufferpunk]

I'm doing a search now, here are a few of RTR's posts on the subject. There are many, many more...

F-8s have a high requirement for alkalinity.

If there is nothing wrong with your tap water, it is best not to do water modification. If you use substrates which dissolve and harden the water, you do need to hold your freshly drawn water in reservoirs with those materials so that the can be pre-equilibrated with the higher KH and pH before you add them to the tank. Otherwise you are allowing the water to change in the tank, replacing it different water (both KH and pH different) and then gradually adapt until it is time to change water again next week. That is not stability.

Water modification is possible and not especially hard. But it requires time and pretreatment. Therefore it costs money and space and time. Doing in-tank changes is poor fish-keeping practices. Routine water changes anre not counter-productive, they are bringing the water back to where it was a week ago. If you do a partial and the start changing the water profile in the tank, you are not reaching stability, you are guaranteeing constant instability with 24/7 changes in water profile. If you want to use modified water, you need to do the modification before it goes into the tank with the fish. Otherwise you are better off with acceptable tap water.

In the wild fish may handle wide ranges of water profile over the course of a year. But the hazards in the wild are non-trivial. The much longer lives our fish show in captivity (with proper care) are in part from relatively stable conditions. Stable high water quality is non-trivial.

Question #1: Why do you want to "raise the pH permanently"?
-The pH is responsive to and controlled by the KH (carbonate/bicarbonate hardness) of the water. As the KH decreases, the pH drops.
-The KH is used up in bacterial nitrification. Every milli-equivalent of ammonia oxidized to nitrate uses up two milli-equivalents of bicarbonate. That is the nature of aerobic bacterial nitrification. The KH is replenished by water changes and by aragonite substrates and also by dead coral decore (but I cannot honestly suggest that unlees you know that it was harvested already dead). I also have used small canisters with mesh bags of coral rubble (harvested as such) which are swapped out approximately monthly, rinsed and dried while a second bag is in the canister. Those bag by good water flow do help support the KH quite well IME.
-KH is dynamic, it is never "set & forget", so it must be monitored routinely. In hard water and/or low BW tanks, it as variable as nitrate titers. For F-89s it is as important or more so than the specific gravity in low BW tanks. DPs do not seem as sensitive as F-8s to me.
-If liquid commercial buffers are used, IMHO & IME, the tank is doomed. Commercial buffers are one of the best ways I know of to destroy tanks. I never use them, period.

Stability is highly desirable in semi-closed systems. However, that stability is dynamic, it is not and cannot be static. So question #2 is: Why do you think a high pH/KH is important in this tank?
-Stability is good, and water parameters should always be compared to the baseline water parameters. But is dynamic, not static. Nitrates and DOC tend to increase with time. Nitrates may be markedly reduced by LR in SW tanks or by live plants in FW or low BW tanks. DOCs may be reduced by skimmer in SW tanks and by partial water changes in all others. Calcium and/or magnesium levels may be supported by aragonite substrates and/or coral rublle canisters. Carbonates/bicarbonates are supported by aragonite and/or coral rubble,
FYI: Argonite is much more soluble than crushed coral, so is much more effective in supporting those parameters than is crushed coral.
FYI: To be effective, coral rubble may be harmed by biofilm blocking solution of the minerals. If it is used as a supplement, it does better overall if regularly rinsed and dried.

[Pufferpunk]

If you do a search for RTR's posts on hardness & F8s, there are countless ones here.

[bigpuff]

Thank you very much for that! I'm so sorry, it's so sad he went blind. I'm sure that research would've been incredibly helpful not just for F8 care but for all puffer care.

[Pufferpunk]

I offered to buy him a talking typewriter but he wouldn't let me.

[moh]

So as Im going through and doing research, trying to decide if I can really establish a brackish tank, I came across this post. And now Im confused. Does adding marine salt affect the ph and kh of the water? My tap ph is at 8.4 and I dont remember the exact kh measurment but it was high when my LFS tested it for me. So will adding marine salt raise my ph more? Then Ill have to attempt to lower it like I do for my dwarf puffer tank (half ro half tap, brings ph down a bit without needing to supplement buffers). If I go brackish this is the last thing I want to have to do and Im already afraid of going brackish. I dont want to be measuring ro, measuring tap, measuring salt. That would become very difficult to maintain stable conditions.

[sgtmyers88]

It really is impossible to keep a stable GH/KH, if that's what you're thinking. I really wish I could contact RTR about this for a better explanation. I'm just going by what he has posted on this subject the past. It's all on this site somewhere. Unfortunately, he went blind before he wrote his F8 article, which was supposed to be on his 20 years of research for this species.

I wondered what happened to RTR. So sorry to hear about that. Send him my best wishes.

And I agree this is a good discussion thread. It can be easy to forget that its not just salinity of the water but the hardness of it as well for our puffers well being. They go hand in hand.
With that being said AVOID using driftwood. It can soften and discolor the water.

[Pufferpunk]

RTR is practically blind now, he's withdrawn from this site. Stopped answering my emails months ago.

[Iliveinazoo]

So as Im going through and doing research, trying to decide if I can really establish a brackish tank, I came across this post. And now Im confused. Does adding marine salt affect the ph and kh of the water? My tap ph is at 8.4 and I dont remember the exact kh measurment but it was high when my LFS tested it for me. So will adding marine salt raise my ph more? Then Ill have to attempt to lower it like I do for my dwarf puffer tank (half ro half tap, brings ph down a bit without needing to supplement buffers). If I go brackish this is the last thing I want to have to do and Im already afraid of going brackish. I dont want to be measuring ro, measuring tap, measuring salt. That would become very difficult to maintain stable conditions.

The rate at which calcium dissolves slows at higher pH levels so I wouldn't worry about it, you might want to source marine salt with lower levels of magnesium and/or calcium though.