Brackish water - The border between BW and SW?

[SBJ]

Hi Guys

I have been keeping BW and SW aquariums for quite some time now, mostly BW.
Latlely I have been thinking a lot about the boundary between BW and SW(Brackish Water and Salt Water).

In other words: How high can i go with the sg without treating the aquarium like it was a marine aquarium?
In other terms, the highest specific gravity that can still be kept under FW(Fresh Water) conditions.

The reason for me being curious is that i have noticed that quite a few people keep some, marine fish in BW systems with a low sg in terms of marine fish but high regarding BW.

As for myself I only have reef aquariums, I have never tried fish only, but a lot of people say that they can be kept on a sg as low as 1.018, but there would be no benefits if you would have to treat this like a SW aquarium.

I hope you know what I mean. And I do hope you can provide me with the answers I am looking for.

Best Regards

SBJ

 

[joe jaskot]

A brackish water aquarium has a specific gravity below 1.021. 1.021 and above is considered marine. However, most brackish water fish do well in an aquarium with a specific gravity between 1.005 and 1.015.

 

[SBJ]

Hi Joe

So you think that it would be possible to maintain a BW aquarium below 1.021 sg without a swamp, skimmer, etc? And with internal filtration as if it was fresh water?

 

[fugupuff]

Hi Joe

So you think that it would be possible to maintain a BW aquarium below 1.021 sg without a swamp, skimmer, etc? And with internal filtration as if it was fresh water?

yes, you can actually keep marine fish in low salinity as well. My friend sets up huge displays for offices, and all their marine tanks are kept at 1.018-1.020 specific gravity, long term. Different oceans vary in salinity.

You can keep marine fish without a skimmer etc., most people use skimmer is because its more difficult to change water and easier to remove organics from water with skimmer, reducing water change frequencies

Look up primary marine fish and secondary marine fish. Secondary marine fish, evolved from a freshwater ancestry, which many thrive in lower salinity conditions. I was in Hawaii last week, and saw convict tangs, goat fish, porcupine puffers, caranx sp. "jacks", greater barracuda, jellyfish, all in a river about 1 mile from the ocean.

 

[Dieselfool]

I was just going to post up a similar question. I've been thinking about setting up my new 220 like this as well. Would really like to set up a FOWLR tank, but don't have the time to look after this kind of set up. So I'm wondering what kind of colorfull, intresting S/W fish I could keep in a high-end B/W tank? Hey Fug, you mention looking up secondary marine fish. Where would I look that up to get some ideas? I tried Googling it but didn't get much. Lots of stuff about B/W though. Although Achers, Scats and Puffers don't intrest me too much, I do like Monos (Sebea/Argetus), maybe because they look so S/W. Yes I do know they get very large. (LOL) Any ideas?
Thanks.