figure eights in freshwater? with plecs?

[Pufferpunk]

Without a _controlled_ experiment putting large numbers of T. biocellatus from a _single population_ into a bunch of freshwater and brackish water tanks each exposed to _identical maintenance regimes and diets_, we will never know for sure whether brackish water trumps freshwater.

We are still waiting for RTR's findings on his 10 year experiment similar to this, to be published here.

[coldmachineUK]

I thought you'd already been convinced Neale, with having moved F8s from FW to BW in your brackish faq?

[nmonks]

I'm not saying figure-8s don't do well, if not best, in brackish water aquaria. What I am confused about is why. They don't seem to be brackish water fish in the wild. So the story may be more complex that just a bunch of aquarists saying the collectors in Southeast Asia are "wrong".

There are lots of fish that do better in brackish water but are not brackish water fish in the wild. Mollies I mentioned, but also bumblebee gobies, which live, in many cases, in soft/acid blackwater streams. It is 100% unambiguous that these fishes live in freshwater their entire lives. So why do they do best in brackish water?

But the bigger issue for me is that aquarium forums can be a little aggressive sometimes. There's a certain lack of humility when dealing with people who hold different beliefs or have different experiences.

Cheers, Neale

[coldmachineUK]

Absolutely agree with that. I did have my signature with a list of forums I would recommend for people (friendly) and a couple I definitely wouldn't (unfriendly), but I took it down. It seems there's a lot of black and white opinion on certain forums but I don't think this is one of them at all. I think this is one of the most open minded, helpful and friendly, in fact. I don't cringe about posting a question on here.

I think the responses in this thread relate to the B&W approach taken by many. If someone says "theyre only FW" then yes, it will guarantee a reaction from people who disagree. Likewise, if someone says "theyre only BW" then a reaction will take place. The Internet is not a great place for making blanket assertions
As you say, the truth lies somewhere in the middle.

With gobies though, I wonder if amphidromy comes in to play with BBGs/gobiidae as a whole? I know that many gobies migrate from FW to BW/SW during different life stages. I think many spawn in BW/SW and live out their juvenile stage there before moving on to (more competitive (i.e. food) presumably) FW climes and then live out their adult lives in FW.
BBGs may be equipped to do the same even if they don't normally exhibit that behaviour in the wild.

With puffers though, I know a lot less.

[nmonks]

Bumblebee gobies are problematical on many levels. Amphidromy probably isn't an issue in many cases, because they don't have planktonic larvae (as far as I know) and they certainly don't migrate. Another issue with BBGs is that there are multiple species in the trade but no consistent way to distinguish them. So for the average aquarist, Brachygobius sp. is as good as the taxonomy gets. I'd wager that most BBGs die in captivity not because of water quality or chemistry issues but because of diet: they are simply difficult to feed. Not impossible, but difficult, especially in a busy aquarium or if the aquarist is only interested in using dried foods or flake.

As for figure-8s, I don't know the explanation. But I think there is a gap between what works well in aquarium (low-end brackish) and what they inhabit in the wild (freshwater). I haven't seen any convincing explanations for this. My guess would be some hidden factor, like nitrate, is the key, rather than salinity itself.

Cheers, Neale

[kimmers318]

Wow! This has been an interesting thread to read thru. Fig 8's are one of the species I have considered keeping in the future, and probably would have ended up with them if I hadn't have found my modestus. Now, I have to wonder if my nice hard water wouldn't be perfect without it's salt to make it brackish. I only have test strips from jungle labs to test hardness and the reads don't come up in single digits like I normally see but the alkalinity comes up as 300, highest reading on the chart, and total hardness (gh) is also 300, again the highest read on the chart. In the past I tried all kinds of things to lower my water hardness and finally gave up because as mentioned, it would just swing back up and the swings were harder on the fish than adapting to the harder water.

[Pufferpunk]

Forget about the test strips. Get a liquid test kit (like from Aquarium Pharmaceuticals). It will be more difficult for most folks to acheive hard water for them, than to just add salt.

[kimmers318]

Couldn't find a GH liquid test kit when I bought these, only a KH liquid test kit, why they wouldn't have both I have no idea. But the KH comes up at 11 drops to change it from blue to yellow, will have to look again for the liquid GH kit. I know I have hard water because I use a mineralizing system to soften it every year for the pool and see the hard water buildup around faucets and such.

[RTR]

Since my games with F-8s were entirely tank associated, I know little about their natural lifespans in the wild. I did learn that light brackish was most effective for long life in captivity, especially as solitary specimens. There were hints that high GH & KH (both at or above 9-10) FW was better than my tap water (GH ~7, KH 7-9 seasonally), but not enough animals were involved for showing significance.

In the wild, reproduction counts very heavily. In captivity for these puffers, reproduction is not in the equation as yet, so lifespan and health are all that matters. Two quite different criteria there. Here we talk about sustaining wild-caught specimens in captivity, period. Once we have learned to breed the BW puffers (as now defined by long-term maintenance criteria) we may have to re-elvaluate their handling if breeding requires differnt conditions. Until then, we have to operate on current best info.