Can I use tap water for a brackish tank?

  1. scottishduck Member Member

    Title says it all.

    I am aware of the pitfalls when it comes to marine tanks and tap water and why you use RO/DI water.

    Most people use tap water just fine for freshwater tank.

    I was wondering if you can use tap water for brackish tanks or not.

    I am most interested in gobies (specifically bumblebee gobies). Many are sold as freshwater (when they shouldn't be) so, in a freshwater setup they would likely be in tap water anyway... From what I've read, they like harder water anyway (one of the reasons to use RO/DI would be to keep TDS down).

    Any thoughts on, or more importantly, experience with using tap water with a brackish tank.
  2. SuzanaBanana Member Member

    I used tap water for my brackish fiddler crab tank and they did just fine
  3. hampalong Fishlore VIP Member

    Yes you can use tapwater. Brackish water varies a lot on a daily basis (tidal) so don't worry about keeping the salinity constant.

    Bumblebee gobies occur naturally in brackish and freshwater.
  4. scottishduck Member Member


    I have plans to (someday) get a large reef tank. And I will make the RO/DI investment then... but in the meantime, I'd love to get a brackish tank set up and using tap water would be great because I can focus my funds on other things instead.

    I guess I'll ask my next question, because it relates to what hampalong mentioned with variable salinity.

    I plan to set up the estuary biotope as best I can... would it make sense to control the salinity by varying it with water changes? For example, do water changes with freshwater and manually add salt throughout the week to raise it up. Sort of a salt cycle between 1.004 and 1.010 for example?

    Or would it be better to "just get close" to 1.006 with every change, for example.

    Additionally, from what I understand, you can initiate breeding behavior by adding freshwater at a slightly lower temperature... simulating rain and ensuing floods.
  5. hampalong Fishlore VIP Member


    Do a water change without adding salt, then the next one with salt... or add gradually as you say... as long as it's within range it doesn't matter. Salinity in estuaries changes with the tides, and also with the amount of freshwater coming out of the river. So the rainfall hundreds of miles away, which determines the river level, affects the salinity for brackish fish. Also the fish move around through different salinities within minutes....

    Cool huh? :)
  6. scottishduck Member Member

    Now I just have to decide if I want a small species only, or if I wanna throw something else in there... thanks for all your answers!
  7. pineapples1 Initiate Member


    This is my brackish bumblebee goby tank I only use tap water and I was using prime until recently switching to supa chlor.

    TDS goes of the charts in brackish anyway I don't really worry about it.

    1.Make sure your tank is cycled properly brackish takes longer than fresh.

    2. Bumblebees require live foods they are very picky

    3. Don't overstock they are territorial

    4. Buy an SG meter and try to keep it between 1.002-1.008 fluctuations aren't important as long as it's in between also salt doesn't evaporate so don't add salt when topping up.

    5. Bumblebee gobies breed in monsoon season so if you want to simulate that simply add extra fresh water. Put lots of shells, barnacles (caves) they like to move around this also helps with your water hardness.

    If you want any more help with these feel free to message me.
  8. scottishduck Member Member

    Thanks for the info. Will continue to post questions.

    Would lava rock be appropriate in a bbg tank? Starting to scape it out.


    And since you replied to my question about plants in another thread, is that corkscrew val? Or is there a separate twisted val?
  9. pineapples1 Initiate Member

    I think it's the same val just different people calling it different names. The trick is to not plant it too deeply. I let the roots show a little and it grows like crazy.

    Lava rock should be fine I'm pretty sure it's PH neutral wood will lower your ph so keep an eye on it but if you have enough shell etc to keep the water hard it should be fine.

    How many BB's are you planning on getting and what size is your tank?
  10. scottishduck Member Member

    I would be adding crushed coral to my filter to help keep the pH up. I might also add that in my other (freshwater) tank with large driftwood, my pH hovers around 8.1. My tap water is pH 8.2, KH 5.5.

    I'm still deciding between a species only 10gal (as depicted above) or a bbg/knight goby 20L. There will be PLENTY of shells and hiding places regardless of tank size. I have an easy spot for a 10gal, but not the 20L. Either way, I plan to run a clean set up with a canister filter and inline heater to get the equipment out of the tank.

    Once I finalize tank size, I'll look at stocking numbers. Some other people on these boards suggested that 6 bbg in a 10gal species only would be okay with high enough filtration.
  11. pineapples1 Initiate Member

    I wouldn't put more than 2 in a 10gal and preferably male and female too.

    BBgs have no swim bladder so they hang around on the ground or on the glass mostly and are territorial. Even though the tank/bio load will handle it with too many you will get fights over territory. I've had 6 in 120L which is about 30gal and that was crowded.
  12. scottishduck Member Member

    Thanks for the continued advice.
  13. pineapples1 Initiate Member

    Honestly if you can get a male and female and get them to breed it's awesome to watch.

    The male turns bright yellow and chases her around all day until she lays eggs in the cave, then he guards them for about 2 weeks until they hatch. The fry are tiny and a bit tricky to take care of but plenty of stuff on the Google if you get to that stage.
  14. pineapples1 Initiate Member

    Here's my BBGs getting ready to breed again.
    Sometimes it takes a few days but as soon as he can get her to stay in his cave long enough to lay eggs it's done. Then he'll kick her out and guard them until they hatch.
  15. scottishduck Member Member

    Link broken (on my end anyway).

    Also, what species are yours? And where do you live? Since you have some breeding I thought maybe I might be able to persuade you to sell me some when the time comes. :) My LFS carries them in the freshwater section but doesn't list the species. It would be nice to know exactly what I'm getting. (I haven't had a chance to ask them what they are yet).
  16. pineapples1 Initiate Member

    This is the species I have they can live in freshwater but only for about 12 months then they need brackish they can live for up to 10 years in brackish water.

    I'm in Australia so no chance of getting them from me I'm sure you'll find the right ones. Google is the best for checking species.
  17. scottishduck Member Member

    Calling pineapples1.

    I'm beginning to think about substrate. Originally I was thinking a natural sand. But to keep costs down I was wondering if I could use something I already have.

    I have a bag of crushed coral and 2 buckets of aquarium gravel currently unused. Are either of these appropriate for bumblebee gobies?

    And a final question. Have you ever kept Orange Chromides? Would they be okay with bumblebee gobies (in a larger tank, of course)?
  18. pineapples1 Initiate Member

    They do prefer harder water so the crushed coral would be ok I use sand as these guys spend most of their time on the bottom of the tank. They are territorial but they won't hunt something down, they are an ambush predator that will only eat food that drifts by them.
    I've never had chromides so I'm not sure but don't keep them with anything that is fast they will eat all of the food before it gets to the goby. If you want them to breed keep them on their own they breed in monsoon season in nature so a water change adding only fresh water sets them off and 5-6 days after laying the eggs you'll have fry (goby fry are really hard to raise you need the right foods immediately and you need to get them out or they will get eaten)

    You might want to invest in a syringe or turkey baster so you can spot feed if you want to have a community tank.

    Blackworms are the easiest live foods that I've food to culture.
    Daphnia and brine shrimp work well too.