Brakish question...

[Shocker6966]

Now, I know that brakish fish need brakish water for longevity, but can survive in either full on salt or fresh water for extended periods. What about freshwater fish? Are there some that can survive in brakish or semi-brakish water? I understand that brakish fish have adaptations to handle disolved salts, and that freshwater fish don't. But would it be at all feasable to do a rotating cycle between brakish and fresh by allowing salt levels to drop and then gradually raise them again in order to keep fresh and brakish fish in the same tank.

By now you're thinking WTF is this guy thinking, so I'll tell you. Archer fish and African Butterfly Fish are both top dwelling insect hunters. One hunts by using jets of water to knock bugs from their perches into the water, the other has a remarkable jumping ability and uses it to catch airborne insects. One is freshwater, the other is brakish. My thought was that if I could mix these two species in one half-full long tank, and give them plenty of insects to hunt, this could possibly be the most interesting and entertaining tanks to watch. I do however think it's a pipe dream. I'm going to guess that the butterfly could survive in brakish water, but would die a young and stressed fish, and the archer would meet the same fate in fresh but if anyone knows different, I'd be overjoyed to hear it.

 

[WeeNe858]

most archers are kept in straight freshwater when sold... and african butterfly's are also... ushually you can have a little bit of salt and have them both happy

 

[virginia.lane]

well, a damsel can live in fresh and a molly can live in fresh brackish or salt-we all know that though.. there are certain fish which migrate from salt to fresh, such as certain damsels - neon blue damsel for instance. the strange thing about salt versus freshwater fish is that freshwater fish take up fresh water, flush the water through their gills and take in the traces of salt, whereas saltwater fish take up saltwater, flush the salt through their gills and take in fresh water. It keeps the cells from rupturing. kinda like when a human drinks saltwater, they get dehydrated.. the salt dehydrates us and the more saltwater we drink, the more dehydrated we get till we eventually die of dehydration. So, taking that into consideration one should never subject a fish from either extreme to the other.. the shock would be like putting a fish in boiling water.. painful and deadly! however, since brackish water fish can live in fresh, and fresh can tolerate salt to a degree, it is possible to keep archers and butterflies in one setup. but rather than using pure fresh or brackish, find a happy medium. think of it as a community aquarium where all fish in it live in an environment with a ph of 7.0, even though some fish may live in 6.5 or 7.5 in nature. If you've ever owned a saltwater fish, you'd know how imperative it is to gradually introduce a new fish to a new aquarium. osmotic shock can be highly stressful or deadly to a fish, weakening the immune system and creating a breeding ground for fungi and protozoa to wreak havoc. If you slowly introduced tank water in the bags containing the fish one cup every 15 minutes (example) for an hour while scooping out bag water as well, keeping water level in bag the same (this not only helps with osmotic shock but reduces fish loss due to changes in nitrate nitrite and ammonia buildup-fish bags can have VERY rapid spikes due to feces and what not), then the fish will be under nowhere near as much stress than if you floated the bags first then put the fish in the tank. Remember if either fish shows an adverse reaction, remove it immediately to part tank water part aged water-never put the fish in clean unsalted water after being in brackish because we once again will get osmotic shock, which can kill your fish. I know that I have kept damsels in fresh and molles in salt, but that was something that took several several hours to complete, especially for the damsels. just watch both fish species for adverse reactions and remember, it's better to have two slightly stressed fish than one highly stressed and one happy fish, so part brackish would be best for both parties. don't cater to both creating a one month fresh one month brackish cycle, because that will be detrimental to their health. I hope this isn't too confusing and I hope it helps.

 

[Sploke]

it's better to have two slightly stressed fish than one highly stressed and one happy fish

But if it could be avoided, wouldn't it be better to have no stressed fish at all? Fish adjusting to different pHs is different than adjusting to different salinity. Brackish and saltwater fish have biological mechanisms for removing salt from their bodies that freshwater fish lack. When a freshwater fish is put in a tank long term with an improper salinity, its just a matter of time before that fish is no longer able to cope with the conditions and dies. In short, I agree that it is an awesome idea and would be a very cool tank, but I wouldn't recommend trying it.

 

[virginia.lane]

of course it would be better. that's common sense. I was referring to when a person wants two fish from different biotopes in one enclosure that if your choices were one very unhealthy fish and one healthy one versus two semi unhappy ones, then it would be better if you used a common ground for both fish. obviously keeping both species in their own habtats is the most effective. obviously salinity versus ph is different in terms of a fish's ability to adjust and the cause and effect of ph versus salinity. it was merely an example to show that if a happy medium in attained, two fish can live together in one tank from different regions. since we aren't talking about putting a freshwater fish in pure salt, it is possible. it meraly depends on the species. saltwater by nature has a higher ph than freshwater excluding some cichlid biotopes, therefore any fish subject to a salt environment must first be able to live comfortably in a high ph environment. a neon tetra for instance cannot nor should not live in a high ph environment. the effect would be called alkalosis. signs are milky skin, shedding skin, errosion of the gills, frayed fins, jumping, flashing, darting, shimmy, gasping, reddened gills, blood streaks, increased respiration, clampd fins, and of course, death. before a fish is even considered for a brackish tank, it must first be determined what ph range it prefers, then whether or not it can live in an aquarium given a salt bath. it isn't just a salinity issue, it is also a ph issue. you never want acidosis or alkalosis. most people who have sick fish assume it's a water quality issue or the pet shops fault. they never realize the fish is in shock from the sudden ph shift. shock can take from minutes to days to surface, depending on what the cause and effect were. in any situation with adverse conditions it's only a matter of time before the fish suffers and dies. that's generally due to putting a fish in an environment without weighing pros and cons and doing enough research. it is quite possible to put a freshwater fish in a brackish tank with little to no ill effect long or short term, so long as the change to brackish or brackish to fresh is gradual. brackish water is freshwater from the faucet with one tablespoon of aquarium salt added to each five gallons of the freshwater. this is the same concentration of aquarium salt that is part of the recommended treatment for stress and disease. almost all aquarium fish can tolerate brackish water with one tablespoon of aquarium salt per each five gallons of water. for example, all Livebearers, all Cichlids, all Goldfish and Koi, all Barbs, all Gouramis, and all Danios can tolerate this amount of Aquarium Salt. the "mechanism" you are referring to that "brackish and saltwater fish have in removing salt from their bodies that freshwater fish lack", is called osmotic regulation. freshwater fish also have osmotic regulation. a sudden environmental change causes an imbalance in osmotic regulation, thus causing osmotic shock, which I have previously mentioned. marine fish live in a medium of greater concentration than their body fluids. this means that they tend to gain salts by diffusion and lose water by osmosis. to offset the loss by osmosis, they drink sea water, most of which their kidneys are able to retain – the salt is excreted, often through special cells in the gills. freshwater fish have the opposite problem and have relatively large kidneys to excrete the water entering their body by osmosis. to offset the loss of salts, freshwater fish can obtain salts from their food. many also have salt absorbing cells in their gills and mouths. they drink very little water and take in very little with their food. several species, such as the Salmon, travel between sea water and fresh water and they therefore have to spend a short period in brackish water to allow their bodies to adapt to the new conditions. http://www.marietta.edu/~mcshaffd/aquatic/sextant/excrete.htm

 

[Sploke]

My main issue with that last post is that brackish water simply cannot be made by adding aquarium salt to tap water. It's been debated up and down on this forum, but the end result is that's incorrect. Aquarium salt is plain NaCl, same as table salt. Even sea salts from the grocery store are not the same thing. When seawater is dehydrated to obtain the salts, there are many different reactions and changes to the substance that are not simply undone when it is rehydrated.

Technically speaking, brackish water is any natural water that is some mix of freshwater and seawater. To make true brackish water, you need to use marine mix, because that is how you would make seawater. Reef keepers use marine mix, not aquarium salt, to make their marine water for a reason.

I use 1 cup of salt to a 5gal bucket, which gets me a salinity of somewhere around 1.010, middle range brackish. Some people go higher salinity, many keep it around 1.005, which is fine for many brackish fish. However, saying that brackish water is "tap water with aquarium salt added" is incorrect.

 

[wataugachicken]

this would be a very bad idea. changes in salinity need to be done slowly and in small amounts to allow the fish to acclimate and settle before it is changed again, and most often they are only done one way (fresh to brackish to marine). constantly changing the salinity is going to stress the fish to the point of death.

And just as sploke said, brackish is freshwater + seawater (marine mix salts) not freshwater with aquarium salt. that's not brackish, just unnecessarily salty freshwater.

 

[fish_freak]

I would not recomend this. While the archers could survive in fresh water for a time as they get older they really need salt in there water. I dont think the butterfly fish would last more than a couple of months in a brackish set up. Heres in idea for you though. You could silicone a peice of glass in the middle of the tank almost to the top but leave enough room for the bugs to get back and forth. Run it as two seperate systems with seperate heaters and filters on each side. It would be almost like haveing them together and I think the best option if you want both species.

 

[virginia.lane]

"My main issue with that last post is that brackish water simply cannot be made by adding aquarium salt to tap water."

by aquarium salt, I am referring to any sea salts used in an aquarium, not table salt, or anything like aquarium pharmeceuticals freshwater specific aquarium salt. I wouln't be caught dead subjecting my fish to that. In seawater, the ions are dominated by Cl- (19.353 gr/kg), Na+ (10.76 gr/kg), SO4-2 (2.712 gr/kg), Mg+2 (1.294 gr/kg), Ca+2 (0.413 gr/kg), K+ (0.387 gr/kg), HCO3- (0.142 gr/kg), Br- (0.067 gr/kg), and Sr+2 (0.008 gr/kg); other ions are present in trace amounts, including gold. Freshwater contains similar ions, but the amounts are highly variable and depend on season, amount of rainfall, type of rocks, etc. therefore, anyone wishing to add salt to an aquarium whether it be fresh brackish or marine, should not use anything with strictly NaCL. Now, by tap water, I am referring to water which is not collected in any body of water or from a gutter. Most people use tap water for there fish. Obviously, unless you have well water (which yes, still has mineral deposits and heavy metal which need treatment for use in aquariums), it has to be treated for chlorine, chloramine, ammonia, heavy metals, etc. "tap water and salt" is brackish water, just not in the naked bare minimum LITERAL sense like you thought I had meant. It is and it isn't.. It is in the sense that it isn't runnoff water and salt or pond water and salt or sewage water and salt etc., but not in the sense of any water supply untreated for safe use in an aquarium environment. Hope that clarifies that!

Back to the issue at hand, I personally would not try to put two species with such diverse needs together-especially if they are not migratory animals which in the wild travel from fresh to salt, and therefore are use to fluctuations in salinity. If you really want to, in the end that's purely up to you. If it works, bravo! If not, lesson learned. Best of luck!

 

[virginia.lane]

I just googled the compatabilty of butterfly fish and archer fish, and found out on at least 30 different sites that they are both compatable species. I read on several occasions that they are both highly tolerant of different water conditions, so your little experiment is quite feasible! In fact, out of all the miscellaneous fish mentioned per site, the archer and butterfly are the most compatible in terms of aggressiveness, liveliness, hardiness, and disease resistance. Best of luck and enjoy your weekend!