Hello I have a 50 litre I was going to use for hillstream loaches but have since decided to try a brackish tank. Can you please help me with a few questions?

1. Can I use natural sea water mixed with tap water or do I need to use expensive marine salt mixes?

2. About how much does a basic hydrometer cost?

3. What should I stock it with the only brackish fish I have seen for sale are mollies (which I am not a huge fan of) and orange chromides that are not suited to a tank that is only 50 litres. I have seen a bumble bee gobie for sale once but have not seen them since. I really like the bumble bee gobies and puffers. Would they be suitable for a 50 litre if I can source some? Can they be kept together?

Thanks :bounce:

1. NSW (natural seawater) and watered down with RO water would be better over using tapwater. Although you can use a saltmix if necessary.

2. I really wouldn't bother with one of these as they are usually very inaccurate.

3. This site should help you with stocking you're tank

Actually Now I am thinking of getting just a figure 8 puffer but I am finding mixed information about them. Are they brackish or freshwater?

I dont mind either way.

Also can they be kept with other fish and if so what ones? :bounce:

They can tolerate in both. I just did a google seach, and it is said (according to wikipedia) that they will live longer in a brackish tank. This is the page here.

They're brackish, but will survive for a while in freshwater.

They are like Salmon - born in freshwater, they migrate as they grow downstream to mangrove swamps and the sea where they live their adult lives, then they return to freshwater rivers to reproduce. The ones you see for sale will almost undoubtedly have been caught in rivers and then transported and quarantined in freshwater, so that is how you should set them up initially. Over time you should SLOWLY change the water to brackish, or even full marine if you are prepared to buy the appropriate equipment to maintain a proper marine tank (skimmer etc.), but you need not do anything for months. DO NOT take them home and immediately dump them into a brackish set-up. They are predatory and will attack and kill most other fish etc. You need a good supply of snails etc. to feed them. I personally think 50 litres is too small for even 1 puffer because they are messy eaters and produce a lot of waste. You'll need a biggertank and a good quality, large capacity filter to keep them healthy.

Here's a good little article:

http://www.thepufferforum.com/forum/lib ... ed-puffers

Hydrometers cost about $10 at the LFS. From what I've read its a bit hit and miss keeping figure 8's and gobie's together, I have two gobie's in with my puffer so I guess time will tell.

I got bumblebee gobies from Hutt Pets - they are way cool and hilarious to watch when you drop something like mosquito larvae into their tank! They will eat so many they have them poking out of their mouths. I have a guppy in with them at the mo and at first they were nibbling its fins but now they co-exist quite happily. And yes i have it set up as brackish, made with tap water and aquarium salt/rock salt.

if you keep bb gobies and say a fig8 puffer the salinity wont need to be over 1.010 so you wont use heaps of salt if you decide to use a marine salt mix (also being only a 50 l tank) this i feel is the safest option as you dont want to introduce ane nasties into the water. however if you decide to get saltwater from the sea i dont think i would be getting it from around the port or even tahuna as the water at the port is very polluted from industy. also be aware bb gobies really need a source of live food be this daphnia, small shrimp , other small water creatures or whiteworms (a variety is best , some will take meaty dead food but it shouldnt be relied on) but congrats on deciding to start a brackish tank with a lil planning and research it will go well

They're brackish, but will survive for a while in freshwater.

Wouldnt we want our fish to survive for more than a while ? LOL