Brackish tank questions

Ok.

I have a 3rd tank that 'needs' to be set up. I was kind of thinking about possibly a brackish set up... unless it's too complicated

Brackish water is where sea water mixes with fresh water in estuaries. However, I guess the salinity is not constant with the sea flux changing every 6 hours or so. What kind of salinity do brackish ecosystem fish take ? does it need to vary every so often ? Is it possible to mix actual sea water (from the wild west) with tap water to obtain the correct mix?

Any particular type of filtration needed ?

I was thinking towards the lines of an archer fish ? what kind of water volume would be recommended for it ? what other fish would be suitable as tank mates ...

Are brackish fish expensive (like marines) or are they more like community fish price wise ?

So many questions ... if you want to add any more information on this type of ecosystem, please do not hesitate.

Thanks and regards,
Valerie

Hi Valerie,

I had a brackish tank for about 8 months which contained two Figure Eight Puffers. They are not that difficult to maintain, but there are considerations over and above a freshwater system.

Firstly, you need to determine the amount of salt that is right for the fish you intend to keep. Salinity is measured by a hydrometer. You'll pick one up in any LFS that sells marines. They're around €20. My puffers needed an SD (spefic gravity or salinity) of 1.005 which is pretty low. Other brackish fish may require a higher SD.

You will obviously need salt. It needs to be marine salt. Please don't confuse this with aquarium salt which is used for treating disease. Again, you'll pick this up in an LFS selling marines for around €20 for a 5kg bag. A 5kg bag lasted me about 2 months doing weekly 40% water changes on a 65l tank. You'll use a lot more salt than you think. It's surprising how much salt is needed to achieve even a low salinity level. I wouldn't use sea water as you risk adding parasites to your tank.

The salinity level in the thank can vary slightly after water changes as this will also happen in a natural brackish environment as the fish move between the salt and freshwater.

If you have a tank that's already established as freshwater, you should slowly convert it to brackish over a period of 4-6 weeks. This is because the nitrifying bacteria in a brackish tank are different to that in a freshwater thank. I did it by using brackish water for water changes which slowly brought the SD up to 1.005 over about 6 weeks. The filters required are the same as for freshwater - I used an internal. I have heard it said that you can use a skimmer on a brackish tank as the salt will cause waste to collect on the surface, but this certainly isn't nesessary.

I haven't seen that many brackish fish in LFS here in Ireland, but those I have seen do appear to be priced closer to tropicals than marines. If you're considering Archers, you need to be aware that they can grow as big as 12\". Therefore, you're looking at a pretty big tank - 200l for one and up to 400l if you want to keep 4. As with freshwater fish, you need to determine if you're mixing species that they are compatible. The puffers I had were not suitable for a community tank and needed a species tank.

Hope this helps.

hi Valerie,
you already ahve brackish fish guppies. you could also consider(depending on size of tank) the four eyed fish(Anableps Anableps) or tooth carp you could also consider mudskippers.


AS for using sea water i would not dismiss it out of hand as you will most likely be keeping at tropical temp plus if you add uv you can kill of any unwanted life forms the down side you will also kill off some helpful life as well

some food for thought

www.fishforums.net/index.php?showtopic=177654

Mickey & Cath

Sound advice above.Nothing to add to the keeping,but I have seen the following for sale here over the last year or so,anableps,archers(12-15euro),'freshwater' morays(gymnothorax),scats,monos,mudskippers,puffers,and various livebearers.I'm sure if you contact the sponsors on here,the lads will be able to give you an idea of what they can get,and you can work it from there,as Ken said,some may require different salinity levels,or species tanks.

Dave