need some help bad

[Ravenfish]

ok i am planning on starting a brackish tank....I allready have a 20g tank that has been running freshwater for about 5 months after it was cycled, and i need to know is it ok to use aquariam salt to make it brackish water(i have read that marine salt is recommended but i kind of cant get the marine salt until i get the fish and since they wont hold the fish any longer for me i need to knojw if temporarily i can use aquariam salt. that and do i have to re-cycle the tank after i make it brackish, and finally aproximately how much salt per gallon should i add. I am planning on gettin one of the following set ups (i know the fish will outgrow the tank and I am allready planning on upgrading, the puffers are being held for me but i have to buy them on friday or another person will be buyin them)

option 1:2 green spotted puffer
option 2:1 green spotted puffer, one figure eight puffer
option 3:1 green spotted puffer and one green scat
option 3:1 figure eight puffer, one green scat, one night goby
option 4: 1 green spotted, one mono, one green scat

need some help asap, dont want to lose the opportunity to get the puffers and other brackish fish, LFS is haveing a sale....All Brackish water fish on friday will be half price, kind of why i asked them to hold the puffers....i know i am a sneaky bastard but that is thier fault for not noticing when i asked them to hold them.

 

[SalmonAfrica]

Hey there

Firstly, it is never recommended that aquarium salt is used. Even though it will show as higher SG in your tank, your fish won't 'accept' these conditions as brackish, and won't survive long term with that salt.

You'll also have to re-cycle your tank once its brackish. Unless, of course, you change the salinity by .002 every week, in which the bacteria will adapt and continue to keep your tank healthy even though they're now in salty water.

When you get the aquarium salt, read the instructions about how much salt per gallon/litre you'll have to use. Some brands use more or less salt per volume water, so it best to check with which brand you use.

Ideally I would rather you just didn't get these fish right until your tank is brackish and you've cycled it fully. These species are relatively common and you should come by them again soon.

For the size tank you have, I'd keep one puffer per tank until you upgrade to the larger sized tank. Once they've settled in they can get a little nippy, and sometimes the injuries can lead to unwanted infections.

The best options there are 3 and 5. But again, not entirely ideal. Scats and monos grow big and produce a lot of waste, not to mention they like being kept in schools. I'd really say (if you are going to get a sufficient upgrade in the future), go for a group of scats or Monos, or if you're not, just keep a single GSP or Figure-8 in the tank you have.