New To Aquatics And New To Brackish Water

[dilbert]

Hi all!

I still haven't got a tank but it looks like it would be a relatively small one. Min. 30 to max. 90 liters I guess.

After reading eventually this Brackish FAQ,

http/homepage.mac.com/nmonks/aquaria/brackfaqpart8.html

my suggested list so far is this:

- Malayan trumpet snail (Melanoides tuberculata)
- Java fern

My guess is to first insert the Java fern and then the snails.

After a week or two, I would like to add some shrimps. But here I am not sure about the right species.

About the Amano shrimps, I read that the adults wouldn't survive in brackish water, others say they would.

Many online stores don't specify exactly if brackish or freshwater and for many shrimps it depends exactly of the species or subspecies if they do brackish or not. How can I avoid trial and error also bearing in mind that many shops won't exactly be knowing what species it is? The sometimes sell only "Name spec.".


If I would really go for a larger tank, I maybe would try to get a

- South Asian horseshoe crab (Carcinoscorpius rotundicauda)


Does anyone know other small invertebrates that could fit into a small brackish tank? Temperatures should range from 18 to 28 °C with an average temp of 22 to 24 °C, so I could omit a heater.

And finally, how will the tank be cycled or balanced if there are no fish in, only snails and another invertebrate species?

 

[nmonks]

Greetings,

Avoid Carcinoscorpius rotundicauda unless you have lots of experience of keeping large, difficult invertebrates and are prepared to keep an animal that, when healthy, will be invisible from view burrowing through mud. Wet Web Media has a nice FAQ on horseshoe crabs that covers the reasons why these animals are extremely challenging.

The variety of brackish water inverts on the market is actually pretty good. I haven't updated the FAQ for a while, so it's a bit limited. Among the best choices are:

Red-nose shrimps
Amano shrimps (to SG 1.005)
Nerite (Puperita pupa, Vitta usnea, Neritina virginea especially)
Freshwater nerites (to SG 1.005)
Freshwater hermit crab (Clibanarius africanus)
Brackish/marine hermit (C. tricolour, SG 1.010+)
Red-claw crab (amphibious)
Fiddler crab (amphibious)
Shore crab (SG 1.010+, very predatory!)
Beadlet anemone (SG 1.018+)

In the wild Amano shrimps do indeed live in brackish water marshes. The larvae develop in the sea, so they have a complex life cycle. As with any invertebrate, acclimating it carefully to new conditions would be a very good idea.

Cycling an invert-only tank is much like cycling a regular tank.

Cheers, Neale

 

[dilbert]

Thank you for the detailed answer. The min/max SG values are also very helpful.

 

[dilbert]

Meanwhile the tank cycles and cycles ... I got another question.

I've read during the endless time I am waiting now that the bacteria inside of the filter of a freshwater tank are different from those in a marine tank.

What bacteria are then in a brackish water tank?

My goal is to stay with SG 1.005 but I was wondering what would happen if the salinity de- or increases? In the extreme case that SG would go against 1.000 what would happen then?

Well, maybe it's different what happens in nature and what would happen in my tank but both cases would interest me.

 

[nmonks]

I've read during the endless time I am waiting now that the bacteria inside of the filter of a freshwater tank are different from those in a marine tank.

Not sure anyone knows for sure if this is the case. I certainly don't. It probably depends on the precise salinity. For all practical purposes it doesn't matter, except to say that dumping live rock into a low-end brackish tank hoping to rapidly mature a filter doesn't work. Putting some freshwater filter bacteria into a low-end brackish tank seems to work OK, especially, if the SG is 1.003 or less. You can then gradually raise the SG to 1.005 and expect to maintain good water quality.

What bacteria are then in a brackish water tank?

No idea. Doesn't matter.

My goal is to stay with SG 1.005 but I was wondering what would happen if the salinity de- or increases? In the extreme case that SG would go against 1.000 what would happen then?

Within reason, the bacteria will adjust. Depends more on the rate at which you change the SG. It would be silly to expect the filter to go from SG 1.015 to SG 1.000 in one water change and be fine. So go up or down a couple of "notches" on the SG scale (e.g., 1.008 to 1.010), leave it there for a week, and monitor water quality. Make further changes as required. There's no real advantage to messing about with SG once the tank is set up though, so you may as well decide on a useful salinity for your fish and stay there. Slight changes might have a tonic effect on the fish, but big ones are not required and potentially risky to the filter.

Cheers, Neale