Logo
Please visit our Sponsors
Brackish Question & Answer Page (FAQs)

We ask that, before submitting, you refer to...
Tips on Asking Questions
Ask the WWM Crew a Question,
Query Corrections Referral Page, FAQs on FAQs. EDFP, TBPFAQs SWPOTD, Last Few Days Accrued FAQs,

Subscribe to the Daily Pics 

Cardisoma sp. (likely C. armatum). Southeast Asia, Indonesia Land Crabs. Soap-Box Crabs for how they're individually shipped (in plastic soap-dishes closed with rubber bands) to prevent cannibalism. To eight inches across... Not a community tank item... Actually not totally aquatic... if you're lucky, yours will crawl out of the tank and leave.  Full Size Link

Updated 8/3/17, Ask us a question: Crew@WetWebMedia.com
Brackish INDEX to Articles and FAQs;
 &
Other S
pecialized Daily FAQs Blogs: General,
Freshwater, Planted Tanks, Ponds,   
Daily Q&A replies/input from the WWM crew: 
Neale Monks, Marco Lichtenberger, Eric Russell, Chuck Rambo, Bob Fenner, are posted here. Moved about, re-organized into individual FAQs files!
 ________________________________________________________________________

Marine and Brackish ideas for a 5 gallon aquarium; Neale/BR      8/3/17
Hey Bob. Just out of curiosity what sort of Marine life would you recommend for a 6 gallon aquarium? I have some Ideas for small creatures such as freshwater shrimp, but no real clue for marine. Nor brackish. Any
suggestions on marine or brackish creatures I could keep in a 5 gallon aquarium?
<For brackish, you're a bit limited by what's commercially traded.
Bumblebee and Rhinohorn Gobies are two possibilities, but I'm a huge fan of Australian Desert Gobies for being much more interesting and easier to breed. They're little better than annuals though, and notorious jumpers, so
you do want to get a group, keep them securely, and get them breeding (which they will, and the fry are big and as easy to rear as Kribs). I'm not aware of much else that'd fit 5 gallons that's widely or even sporadically traded though. Even the smaller brackish water livebearers such as Micropoecilia really need a bit more space than that, though I dare say people have kept them in "nano" tanks at times. Ditto brackish water killifish. On the other hand, there is the brackish water Betta species Betta mahachaiensis, and a singleton might be viable in 5 gallons (mixed sex groups would surely need more space, as per Betta splendens and other bubblenest species). Cheers, Neale.>
Re: Marine and Brackish ideas for a 5 gallon aquarium       8/3/17

Thank you Neal
<Most welcome.>

Green Spotted Puffer - Clownfish Compatibility     7/2/17
Good afternoon,
<Hey Joel>
About two years ago, I purchased a Green Spotted Pufferfish and have been keeping him in a 29 gallon brackish aquarium (currently about 1.010). I do weekly 25% water changes and provide a variety of foods: tilapia is about
50% of it due to lack of Thiaminase, but supplemented with shrimp, clam, and calamari pieces, with offerings of dried algae on some of the "off feeding" days. He hasn't grown as much as expected, though, and currently is about 2.75 inches.
<Okay>
Over the past 6 or 8 months he's also exhibited symptoms of being bored/restless. Combined with the smaller size (one < 3 inch fish in a 29 gallon tank isn't much to look at), I've been thinking about upgrading to a larger tank, perhaps 40-55 gallons, converting to full marine, and adding in a damselfish or small, odd numbered group depending on species.
<Mmm; well, first off; didn't realize the scientific name had changed for this species: Dichotomyctere nigroviridis (Marion de Procé, 1822), Spotted green pufferfish... Am hoping Neale (Monks) will chime in; but as far as I'm aware, this fish is not totally marine, but brackish. And Clownfishes are full concentration marines>
Most of the advice I've seen in the GSP Compatibility page suggests some have success with Humbugs and Dominoes. However, my GSP is on the smaller side and is fairly timid for a GSP, so I'd be concerned with them as tankmates. My understanding is some of the clownfish species may be more moderate in terms of aggression, particularly if a system contains only one specimen. Granted, I have read Pufferpunk's notes that Tomato Clowns have roughed up her GSPs in the past.
Are there any clownfish you would suggest investigating here?
I have been looking at Ocellaris Clowns but would like a second opinion.
Thank you for your time,
Joel
<I'd go with either Ocellaris or Percula Clowns if trying any; and tank-bred specimens at that. These are hardier for aquarium use, and more easy going. Bob Fenner>
/Neale     7/2/17
<<BobF's right in that the species formerly known as Tetraodon nigroviridis, according to some authorities now properly called Dichotomyctere nigroviridis, is a brackish rather than marine puffer. Indeed, wild-caught specimens seem to be invariably collected in rivers rather than the sea. That said, aquarium specimens don't usually do well kept in freshwater indefinitely, while their maintenance in marine systems (as adults, at least) does no harm and may actually be easier thanks to the use of protein skimmers and live rock to keep nitrate levels low. Regardless, I'd not be keeping small specimens in fully marine conditions, or even high-end brackish systems, simply because there's no pressing need to do so, and if they are having to osmoregulate 'harder' than they would do in the wild, that's a stress factor that's easily avoided. Once the fish is upwards of 3-4 inches, then sure, I might think about transitioning it to marine conditions. As always with puffers, companions are hit-and-miss, and will depend very much on the specimens you've got. Some cohabit nicely with robust marines -- damsels, tangs, snappers, and so on -- while others are as nippy in marine tanks as they in any other sort of aquarium. I'd love to be able to deliver a promise here that species X will do fine, but that's not the way puffers work. So while the larger, more robust Premnas clownfish might be about right given space enough to feel secure themselves, but I'd be leery of combining them with the smaller and more easy-going Amphiprion species. Certainly, combining a pufferfish with smaller tankmates is always risky, and you need tankmates that have not only size on their size but also the speed and the personality to handle occasional problems. General purpose damsels fit the bill nicely, Stegastes-type things, while Sergeant Majors in particular striking me as the sort of very shallow water damsels that I've seen living alongside marine puffers around jetties, harbour walls, rocky reefs and so on. Indeed, Sergeant Majors aren't fussy about salinity and can thrive perfectly well down to SG 1.018, all else being equal, which would suit your GSPs rather nicely too. Cheers, Neale.>>
Re: Green Spotted Puffer - Clownfish Compatibility     7/2/17

Thank you for your quick reply! I will do some additional research on the subject prior to moving forward with any plan. Hope you both have a nice day.
<Thank you Joel; you as well. BobF>

Violet dragon goby & diamond killifish?      6/27/17
Hi!
<Meghan,>
I can't thank you enough for the great website & patience with my continued questions about a permanent set up for my violet dragon goby. It seems like the more I learn about brackish fishkeeping the harder it is to settle on a
plan!
<Indeed! That's part of the frustration of this section of the hobby. On the one hand, relatively few species are regularly traded, but on the other hand, the sheer variety of species that are occasionally traded is mind-blowing, including many fabulous species unlike anything else in either freshwater community or marine reef fishkeeping.>
At this point I'm planning on a 55 gallon tank, but I might go with a 75 if I can find an affordable one soon.
<Oftentimes, and you won't hear this said too often, two or three small brackish tanks can actually be funner than one big tank. Because things like gobies, Killies and halfbeaks are small, but specialised, 10-20 gallon tanks with simple (cheap!) heaters and filters can provide an easier way to keep them at their best.>
I currently have my goby in with my wrestling halfbeaks & they get along great. I want to add a mid water fish to the mix.
<Yes, a great combo.>

So I'm thinking about diamond killifish - Adinia multifasciata - these look cool, but I can't find any videos of them.
<Do try their more modern names, Fundulus xenicus or Adinia xenica.>
Are they mainly mid water or would they compete for the halfbeaks' or goby's food & space? My goby is downright timid when it comes to food.
<I haven't kept this species myself, but my impression is that it's a small, docile species with regard to tankmates, though the males are feisty amongst themselves. Pretty standard for Killies, really. They're also strongly herbivorous in the wild, consuming goodly quantities of algae and organic detritus alongside zooplankton and the occasional insect larva. I'd tend to keep them on their own primarily so that they could be bred, but also to ensure the right diet.>
I'd like to keep breeding the halfbeaks & get the killifish to breed, too.
Would the Killies eat the halfbeak fry before I can net them out? And would the halfbeaks eat the killi eggs before I can move them?
<Halfbeaks generally ignore anything on the substrate, so killifish eggs are probably safe. But fry at the surface would be fair game. If we're talking about Wrestling Halfbeaks here, their fry are comparatively large, but brood sizes are variable and sometimes small, so I'd tend not to keep them with anything likely to eat them. While you might get lucky, especially in a big tank with floating plants, I think you'd find both species more productive kept amongst their own kind.>
I couldn't find much information on the behavior & breeding of diamond Killies. Do they need caves or visually separated territories?
<Yes, caves and vertical structures will provide necessary barriers between males.>
Will a sand substrate work?
<Nope. You need lots of feathery plants or a substitute such as killifish breeding mops. Pairs scatter their eggs, though oddly only one or two a day, and so far as I can tell, males defend territories but not the actual eggs. A week or two later you should start seeing fry appear among the floating plants, one or two at a time, and these fry need to be isolated until they're too big to be eaten. If you've bred Ricefish or Dwarf Mosquitofish, you will find this species very similar.>
Do you have any tips for reducing their shyness?
<Probably impossible under aquarium conditions; a lot of these Killies live in big schools, but unless you can house a dozen or so, multiple males will probably be too aggressive to work in small groups. So most aquarists end up with two or three females alongside a single male, and while "safe", such a small group will feel a bit nervous until really settled in.>
Lastly, would SG 1.003 - 1.005 work for all of these species?
<Diamond Killifish, Wrestling Halfbeak and most gobies (you don't tell me your species) should be fine.>
Thank you!
- Meghan
<Welcome. Neale.>
Violet dragon goby & diamond killifish?      6/27/17

<PS Just saw this was re: Violet Goby. Unlikely to actually want to do any harm to Diamond Killifish, but might be a bit big to make them feel secure.
Cheers, Neale.>

Fiddler or Red Clawed Crabs; husbandry         6/26/17
To Whom It May Concern,
<Looks like me today!>
I have a 20 gallon glass aquarium. I live in an apartment and I'm allowed a 20 gallon vivarium/paludarium or a 10 gallon aquatic tank.
<Cool.>
I'm interested in information about Fiddler or Red Clawed crabs.
<Interesting beasts. Red-Claws are probably easier to obtain, but Fiddlers are a bit less likely to kill each other over time because they're so much easier to sex. The males are very intolerant of one another, but a 'harem' of fiddlers including a one or two males and 4-5 females would be perfectly doable in a tank this size. Just make sure there's space enough for the males to avoid each other. Plastic or wood bogwood roots to create a 3D maze of climbing places, shored up with water worn pebbles and coral sand will work nicely. Both species are tropical, so you will need to heat the system. A small aquarium heater in the water could work, but be sure to get one the right size for the amount of water in the tank; more than likely a 25W heater will be ample. I'd suggest clipping an aquarium guard over the heater to prevent the crabs burning themselves. A filter will be important too, but nothing too fancy. A simple internal canister filter will be cheap, functional, and easy to clean. It will need to go under the water completely though, perhaps lying on its side if the water is just a few inches deep.>
All I know is that you need 1/2 play sand & 1/2 dechlorinated 1.010 salt water, and rocks for them to climb.
<More or less. Basically, both species are hardy and adaptable. The precise salinity isn't too important. Something like 10-15 grams per litre of tap water will be fine (normal seawater being 35 grams per litre). Ideally, you'd use a hydrometer to check the salinity (actually, the specific gravity) before use -- you can get cheap and cheerful plastic hydrometers on Amazon and the like for a few dollars. While not particularly accurate, they're fine for brackish water fishkeeping where ball-park numbers are adequate.>
I have tried to read the articles on brackish water, but I'm having a problem understanding how to set up the tank, dietary needs, etc.
<Both these crabs are deposit feeders. In other words, they process mud and sand, extracting algae and organic material. In the home you can feed them virtually anything, from bits of seafood and cooked peas through to fish
flake and specialist crab food. I'd also ensure a good source of iodine, whether in the form of seaweed (sushi nori for example) or else iodine drops sold for marine aquaria, at one-half the recommended dose. Some specialist crustacean foods include iodine -- check, and if yours does, it'll make a great staple.>
I would appreciate any assistance you could give me.
<Hope this helps, Neale.>

Two fiddler crabs flipped over    6/18/17
Hi, I am emailing you about our two fiddler crabs (with a big and small claw)
<Likely two males>
We got them about 6 months ago from Wal-Mart, and I put them in my 10 gal freshwater tank. I did not realize how aggressive they were, and after they ate 3 of my tetras, we put them in a 10 gal tank.
<Okay>
The tank had about 2 inches of water, half sand, and some rocks and shells.
<There is space for them to get all the way out of the water I hope>
I fed the crabs fish food, some small bits of fruits and pieces of fish, such as tuna or sockeye salmon. The crabs both molted several times and got along for the most part.
<Good signs>
This morning both of the crabs were flipped upside down! 1 seems dead and 1 is still moving a bit, what happened?! what can I do?
<Do you have "water quality test kits?"; need to assess "if there's too much of something/s and not enough of others". Fiddlers don't tolerate nitrogenous waste accumulation, a lack of alkaline earths, low alkalinity... I would change out all the water, rinse all materials in the system, re-set up, add Dechloramination to remove sanitizer, and treat w/ a commercial iodide/ate solution as gone over on WWM>
I just read about the crabs needing salt, so I put a tiny bit of aquarium salt by them.
Is there anything I can do?
<See above and WWM (the search tool on every page or all linked to the Fiddler FAQs: http://www.wetwebmedia.com/FiddlerCrabF.htm
Please Help
:(
<Do write back if all is not clear once you've read/studied. Bob Fenner>
Re: two fiddler crabs flipped over   6/19/17

Thank you for your speedy response!
Yes, the tank is half a sand beach, and they can climb the rocks to get out of the water too.
<Ah, good>
We got them after feeling sorry for them at Wal-Mart, but have become quite attached, especially for their "waving" antics. I did not know anything about crabs really.
<Males "wave" to attract females mostly; and to ward off, threaten competing males>
Shortly after adding the salt, they both perked up, flipped over, and started traveling around.
<Ahh! Great news. Could be a few possibilities here... something as simple as Nitrite poisoning... again, I would invest in simple test kits... And adhere to a maintenance schedule; washing, flushing out the substrate>
It was amazing. Most of the posts on your site has things about crabs needing salt.
<Mmm; a bunch to state here; but no doubt orders of magnitude more organisms are killed by mis-use of salts (combinations of metals and non-metals) than aided. How much salt is in your source water? Many organisms need "some", but very few are aided by more being added blindly.
Again, my urging you/all to get use testing gear. A simple hydrometer is of use for specific gravity, indirectly salinity... OR after cleaning, adding about the same amount of sea salt (NOT table/NaCl) to about the same
volume of water each cleaning>
Thanks a bunch!
<Certainly welcome. Bob Fenner>
re: two fiddler crabs flipped over..

Oh I cleaned their tank etc as well.
<Outstanding. BobF>

Mystery blind eels      6/17/17
Hello all good people at WetWebMedia,
It's Ben again!
<Hello Ben!>
I had these photos with me since years ago but I kept on forgetting to ask you about the eel that is being depicted in the photos.
<Goby, not eel...>
I took the pictures myself several years ago, I was talking a walk in a local fish market, when I saw some horseshoe crabs in an aquarium, together with these odd-looking eels. These eels are white-ish (almost pink actually), no eyes, no scales, but have fins, and have very sharp teeth.
Not very long, perhaps only 20 to 30 cms. The seller told me that those eels were captured in in the river, not far from the sea (so it must have been brackish water).
So, any idea what are they? They look like sci-fi alien monster thingies (due to those scary teeth and no eyes!). I did not buy them (though very tempted to) because I know practically nothing about them, their behavior, requirements for feeding etc.
Someday in the future I'd love to set up a brackish water tank special for eels, so I'd like to know what my options are.
Thank you very much in advance!
Best Regards,
Ben
<These are Odontamblyopus species, perhaps Odontamblyopus lacepedii.
Difficult to say without better photos and some understanding of where they were collected. Essentially identical to the commonly traded Violet Goby, but Indo-Pacific rather than South American. Harmless animals despite their
appearance, but best kept on their own or with dissimilar fish (such as livebearers) that won't compete for food. As you say, these fish are brackish in distribution. Cheers, Neale.>



Re: Mystery blind eels      6/17/17
Hello Neale!
<Ben,>
Thank you for the quick and informative reply!
<Welcome.>
So those are not eels, but brackish-water Goby. I'll keep that in mind next time I find any of them again. Glad to know they're harmless, despite looking so fierce.
<Indeed. Their blindness and weirdly textured heads are related to their habitat -- murky muddy burrows and mudflats. Raised lateral line pores provide high resolution "distance touch" using pressure waves, something
humans can't really relate to. Would be a bit like feeling your way around a dark room with your fingertips, except you could feel things several feet/a few metres in front of you, and not just your hands, but your whole
body. All fish have this sense, but these gobies are specialists. I believe their giant heads are more to do with the gulping air and absorbing oxygen across the skin inside there, a useful adaptation in their natural habitat.
Do peruse Google Scholar using the term "Odontamblyopus" -- much interesting science about these interesting genus to be found there. Do also note those Horseshoe Crabs were probably Carcinoscorpius rotundicauda,
a mangrove-dwelling member of the same family as the familiar North American Horseshoe Crab, but with a much higher tolerance for brackish, even freshwater conditions. Fascinating creature, very occasionally traded in aquarium shops as the "Freshwater Horseshoe Crab" though probably cannot tolerate such conditions indefinitely.>
Again, many thanks & Have a nice weekend!
Ben
<And you, Neale.>
Re: Mystery blind eels      6/17/17

Hello again Neale,
<Ben,>
Thank you for the additional information about the Gobies. Very fascinating, such a humble animal but with such complex abilities.
<Indeed! Fish live in a sensory world we can't relate to. Their sight is basically similar to ours, including colour vision, but they also see ultraviolet in some cases, and daytime species at least detect polarised light too, so they know which direction the sunshine is coming from. Shiny silver colours on many open water fish are meant to reflect polarised light "just so", making them invisible to other fish, something that isn't apparent to us, which explains why they don't look particularly well hidden to us. Next up, sound travels much faster and further in water than in air, so their hearing is probably much better than ours. Vibrations travel through the water just as well, even at frequencies not considered sound, but more like ripples or waves. Fish can feel those too, even using them between themselves for communication (if you ever watch fish fighting, you'll see a lot of fin twitching intended to send waves onto the body of the other fish). Smell and taste aren't separate, and in fact many fish have taste buds all over their bodies, catfish famously detecting chemicals equivalent to a single drop of blood in an entire swimming pool. Then there's their electrical and magnetic senses, both of which we lack completely. While only a few fish actively generate electric fields (South American Knifefish for example) many are able to passively detect such fields (most sharks, and probably a lot of things like catfish as well that also hunt hidden prey). Magnetic fields are used to help fish migrate,
famously helping salmon migrate hundreds of miles from the ocean into remote mountain streams. And finally there's the lateral line system, which as we've discussed, is like being able to touch things from a distance.
Taken collectively, this is why so many fish manage without their eyes -- unlike humans, which are strongly visual animals, for fish, eyes are just one of a whole slew of really sophisticated sense organs available to them.
Of course we're not 100% sure fish can feel pain though, but given their sophistication in other ways, I find it hard to imagine they don't, even if mechanically their pain reception isn't detected and processed in exactly the same way as ours.>
As for the Horseshoe Crabs, I will try to obtain more information about it.
The fish market where I saw them is located in Jakarta, Indonesia, and it's still existing, so I will schedule a visit. I remember the fish guy mentioned that those crabs are "Mimi Mintuno" in local Javanese dialect, and that it was caught in mangrove forests area on northern coast of Java.
Perhaps the gobies also came from the same area.
<Almost certainly. Carcinoscorpius 'crabs' are actually a delicacy, I believe collected primarily for the large mass of eggs inside the "head" part of the animal. A friend of mine had them on his travels, and while the cooked eggs were pleasant enough, they were served to him with so much chili in the sauce his eyes were watering!>
Best Regards,
Ben
<Welcome, Neale.>

brackish - bumblebee goby fin problems (BobF?)     5/30/17
Hello,
can you please help me identifying fin problems with my bumblebee goby which I bought just recently. I have SG at 1.003 and they are the only fish in my 25gallon (100L) tank. The system is established (more than 1month old). Please see the attached pictures. They are fully active and eating live daphnia, live Artemia.
Best regards, Dejan
<Hi Dejan. I'm not convinced this is Finrot. Indeed, it's almost certainly not given the fins themselves aren't eroded. Nor does it look like plain vanilla fungus, lacking as it does the fluffy cotton wool-like masses we associated with fungal infections. I'm much more inclined towards an external parasite, either crustacean or worm. Treating these can be difficult, but one approach available to brackish water fishkeepers is to expose their fish to substantial changes in salinity. Half-strength seawater won't harm BBGs, and for short periods, seawater dips should work
nicely. This means you could use salinity to "shock" any external parasites by using saltwater dips, or else stress the parasites and break their life cycle by exposing the fish to half-strength seawater over a few weeks. With few exceptions, external parasites are either marine or freshwater, and tend not to survive in (strongly) brackish conditions. Am asking our boss, Bob F., for his ideas too. Cheers, Neale.>

brackish - bumblebee goby fin problems    /RMF     5/30/17
Hello,
can you please help me identifying fin problems with my bumblebee goby which I bought just recently. I have SG at 1.003 and they are the only fish in my 25gallon (100L) tank. The system is established (more than 1month old). Please see the attached pictures. They are fully active and eating live daphnia, live Artemia.
Best regards, Dejan
<I agree w/ Neale; this appears to be a parasite... I would treat for directly IF Neale's approach at manipulating salinity doesn't remove them; using both a vermifuge (Praziquantel is my choice here) AND arthrocide
(some version of DTHP likely. See here Re: http://www.wetwebmedia.com/fwsubwebindex/fishlicef.htm
Bob Fenner>

Re: brackish - bumblebee goby fin problems (BobF?)      6/3/17
hello Neale and Bob.
First thank you for the answer and tips.
<Most welcome.>
I did try salt-dip (20g marine/1L for 30min) but unfortunately it seems to have no effect. Now (and before salt-dip) the BBGs have fins that appear to be torn and ragged – please see attached file (there is no aggression in the tank).
<I do agree; I would be treating for Finrot to start with, but also elevating background salinity to around SG 1.005-1.010 for a few days or weeks. This will hopefully stress the parasites sufficiently to budge them, or at least break their life cycle. As BobF mentioned, an alternative would be physically remove and/or use commercial anti-helminths and anti-crustacean medications (the latter primarily used to treat things like Anchor Worm). The use of salinity, on the other hand, is less toxic and cheaper, and standard operating procedure on fish farms where euryhaline fishes are being kept, such as sea trout and salmon.>
In this thank I also have Caridina gracilirostris and some plants: Cladophora aegagropila, java moss, java fern and I think I’ll kill the plants if I would increase salinity.
<Can these be removed to another tank temporarily? None of your plants have roots, so removing them to an unheated tank with some ambient (but not direct) sunlight would be fine during the summer months. The shrimps would probably be fine in an unheated tank during the summer, too, but would of course need some sort of basic filtration, even a simple sponge or corner filter running from an air pump.>
The behaviour of fish is normal and they’re eating normally. Does it still look like external parasite?
<Yes. Something is growing beyond the normal length of the fins. Finrot erodes the fins, making the membranes smaller but sometimes leaving the fin rays (i.e., the bones) "dangling" for a while, giving the classic cobweb appearance of Finrot. But if the fins are longer than usual, that's something else.>
Any other suggestions?
<None; see above, or even better, consult a friendly parasitologist with a microscope able to ID the parasite or pathogen. This isn't a disease I've seen before, I confess, but it looks so much like a crustacean parasite of some sort I'd be treating as per Anchor Worm before anything else.>
Best regards and have a nice weekend, Dejan
<Welcome. Cheers, Neale.>

Violet goby ideas     5/14/17
Hi!
<Hello Meghan,>
I'm still playing around with different ideas of how to eventually house my violet dragon goby. Currently it is alone in a 55 gallon brackish tank, SG 1.005 (varies a little with water changes).
<All sounds fine. Precise specific gravity doesn't matter at all. The main thing is that there's "some" salinity, and it's not kept in plain freshwater indefinitely.>
I was thinking about an enormous tank, but I'm concerned with the ongoing cost of marine salt - especially considering 10-20% weekly water changes.
<Weekly water changes won't be necessary if you lightly stock the tank. 2-3 week gaps between water changes will be fine. Monitor nitrate (make sure it doesn't go too high) and pH (make sure it doesn't drop too much) and use these as a guide as to when to do water changes. Fundamentally, water changes are about keeping nitrate low and preventing acidification. We don't do massive weekly water changes to outdoor ponds precisely because
they're modestly stocked and have "natural" ways of avoiding high nitrate levels and fluctuating pH levels. Oh, and one tip -- if you can get old water from a reef tank, that's usually easily good enough to use in a brackish system! Mix with tap water, of course, to get the right salinity, maybe one part reef tank water with three parts tank -- and you'll get something around SG 1.005 that'll be fairly low in nitrate without needing any expense on salt!>
So now I'm thinking about a much smaller tank. 55 gallons - 48" long is the minimum size for the goby.
<Correct, though it's lookalike species, Gobioides peruanus, is considerably smaller.>
I read that dwarf fuzzy lionfish can handle an SG of 1.015 and up. My goby should be fine with that, too. I can even add a protein skimmer.
<While these lionfish (and other, Pterois spp.) do occur in below normal marine salinities, I'm not convinced they inhabit such waters indefinitely.
SG 1.018 would be fine, and standard procedure for many (robust) marines in the 60s and 70s, but SG 1.015? Seems a bit low to me, especially when there *are* true brackish water fish of similar type out there, such as Notesthes robusta and Neovespicula depressifrons, this latter being very similar in size and appearance to Dendrochirus spp. That said, the Dwarf Fuzzy is certainly easier to get, so I will let BobF chime in here before I get too adamant about its suitability or otherwise!>
So I'm thinking about a 55 gallon tank with the goby and some dwarf fuzzy lionfish. I'd love some little blue leg hermit crabs, too, but I'm betting the lions would eat them, right?
<It isn't common, but it does happen, yes. A lot depends on the relative sizes of the lionfish and the hermit crabs' shells.>
Would a 55 gallon be sufficient space for my goby plus 3 or more of the little lions?
<I would think not; when keeping marines, more space is better, especially if you're trying to reduce workload/expense.>
And would live rock work at that low SG? And would the rough surface of the rocks be a danger to the goby?
<Live rock will in theory work, in the sense that once the bacteria colonise the anaerobic crevices, you'll get denitrification alongside nitrification on the aerobic parts of the rock. But the marine invertebrates and algae? Nope, they'll die at reduced salinities, except in a few cases which often end up as little more than green-brown algal slimes. Might as well just get Tufa rock, lava rock or "dead" live rock. Bacteria will colonise these just as well. Will they scratch the gobies?
Well, it's a risk, yes; given these gobies come from muddy rivers and estuaries, abrasive rocks and reefs aren't something they're programmed to deal with. So I'd be looking at bogwood, water worn cobbles, that sort of thing.>
Maybe I should go full strength sea water so I can try corals or something, too. Would the goby be happy & healthy long term at the higher salinity?
<Gobioides broussonnetii can/does live in fully marine habitats. Not coral reefs though, and it might well be stung/irritated by polyps and the like.>
My goby isn't an aggressive feeder - it let Sailfin mollies & guppies munch the food intended for it. That's why it is alone now. Would the lions cause the same problem?
<Keeping them with livebearers is ideal, given that Gobioides are primarily herbivores and detritus feeders in the wild, so they all eat the same stuff. Algae flake, Plec wafers, and a few offerings of small invertebrates such as brine shrimps ticks all the right boxes. Easy peasey. Adding a nocturnal predator complicates things, and obviously would view small livebearers as prey. But shouldn't be a threat to the Gobioides, assuming the latter was much too big to be viewed as food. But predators need meaty food, which means nitrate because a problem more quickly, which would in turn mean more frequent water changes. So do-able, yes, but optimal, probably not.>
Thank you for all the help with my questions!
- Meghan
<Most welcome. Neale.>
re: Violet goby ideas (Bob, Dwarf Lionfish at SG 1.015?)     5/14/17

"Dwarf Fuzzy is certainly easier to get, so I will let BobF chime in here before I get too adamant about its suitability or otherwise!"
<As Neale hints; the genus Dendrochirus Lions can be kept at reduced spg, but not this low permanently. Too damaging to their kidneys, other internal organs. Bob Fenner>
Re: Violet goby ideas (Bob, Dwarf Lionfish at SG 1.015?)     5/15/17

Oh, and let me add Meghan, that you have another crepuscular predator option in the US trade; namely Butis butis, and beautiful species despite its “Crazyfish” moniker. Eminently suitable for life alongside Gobioides and *adult* Sailfin Mollies; will view bite-sized companions as prey. Please see attached for a photo of this underrated gem, a true brackish water specialist adaptable to anything from hard freshwater to full marine, but probably best in middling salinities. Adult length to 15 cm/6 inches; hardy, territorial but otherwise peaceful.
Bottom line, unnecessary to maintain (and possibly stress) a marine predator at suboptimal salinities when there’s a good range of brackish water predators out there to choose from!
Cheers, Neale

Big brackish tank - livestock selection & build     4/14/17
Hi!
I've written to you several times and have always gotten great advice!
Thank you!
<Hey Meghan, Earl here today.>
I have a violet dragon goby that I want to build a big tank for, but I also want to create something really special and have some ideas I want to run past you.
<The size of these guys is such that they would really appreciate the long, low tank you mention below.>
I'm going to build a huge plywood & glass aquarium - 8 ft long, 4 ft wide, and 4 ft deep. I only want to fill it to a depth of about 30 inches so I can make it into a paludarium style tank with above water plants along the back & sides. If my calculations are right, it will hold about 350 gallons of water.
<Very ambitious but excellent! This is a great example of the kind of unusual tank that also represents a biotype. There is a reason you see them in public aquariums these days...a habitat to hopefully inspire and educate
more than being a garden or zoo, if that makes sense. I am definitely inspired by these and a paludarium has been on my to-do list for a long long time! Would love to hear updates as you go, pics, etc. for "prosperity" on WWM. There is a dearth of info online about this and your experiences executing it would be valuable.>
My dream is to use it to house some unusual brackish aquatic critters. SG 1.010 to 1.012. Temp in the mid to high 70's. Use a protein skimmer and sump for filtration.
<I cannot speak as to the functionality of a skimmer in a brackish tank like this but I can say that mechanical filtration, probably carbon as well, would be vital, especially with the debris that plants and their accompanying silt/soil would create. What I would do is definitely to visit public aquaria, maybe zoos or arboretums, park nature centers as well, and try to get hold of the people in charge of their setups. Many of them will be more than willing to chat about this and would be absolutely invaluable resources you will have a very hard time finding elsewhere. Not sure about your location but the Shedd Aquarium in Chicago has a large amount of these setups. Also ask people who keep Amazonian frogs (so-called poison dart frogs and similar). You will be creating something that is also akin to a pond in some ways so people who deal with those (vs. people who are strictly aquarists) may be of use.>
My ideal stock list is as follows:
6+ Indian mudskippers (P. novemradiatus)
3+ fiddler crabs (whichever I can get)
6 banded archer fish (T. jaculatrix)
1 violet dragon goby (G. broussonnetii)
8+ four eye fish (whichever I can get my hands on)
12+ blue leg hermit crabs (C. tricolor)
I have been researching this combo and have run into stern advice against putting many of these together, including on wet web media. But it seemed to me many of the issues revolved around too little space or the large fish making the mud skippers reticent to enter the water. If I can solve these problems they all seem to need the same kind of temperatures, do well in similar salinities, etc. If I can pull it off, it would be one heck of a tank!
<It'd be hard to overstate the number or severity of problems that are primarily tied to crowding issues. The setup you propose could indeed help with this but have a plan B. Having animals from a similar region is the way to go IMHO. Offhand, paludarium can/should be segmented via a series of walls or weirs and that could be used to mitigate the issue of the skippers avoiding deeper water with large fish. Possibly helping them ease into deeper water as they desire over time? Just spitballin', there is a near limitless number of ways to set this up especially if you build from scratch. Very exciting.>
I've been thinking about how to build an environment where they will all feel comfortable, and my idea is as follows:
On one side of the tank build a shallow area where the water is only a few inches deep (against the front of the tank), that then slopes up to a sandy land area (against the back) for the mudskippers & fiddler crabs. Put some
plants & rocks/caves along the back of this beach. On the side of the shallow water & beach have a steep slope into deeper water.
<Sounds good. Again, check out other displays for inspiration.>
I'm debating how to build this slope & shallows/beach.
I'm thinking a "false bottom" like you see in dart frog vivariums.
Basically a hallow, permeable support structure for drainage with a circulation pump underneath. Wrap it with fiberglass screen and put the sand/gravel substrate on top.
<Beware of fiberglass screens. I myself had a sad "adventure" with them several years back which you can read about on WWM that involved a tank wipe due to the fact that some fiberglass is impregnated with a fireproofing substance that is toxic. Be on the lookout. On another note, the plan you describe seems very high maintenance, perhaps even overly complex. I find the low-tech, low-maintenance route the way to go whenever possible. Especially if it's more failsafe. Ask yourself, "if this needs taken apart, how possible will that be and will I be willing to do it?"
Again, hard to nail this down without going so far as to draw out some blueprints.>
I could completely enclose the underwater area beneath (and hide the heater, pumps, etc here).
<Easily hidden behind plants, rocks, but must be easily accessible for maintenance.>
Or I could make it open, like an underwater ledge or overhang. Use disguised pillars to support it. I bet the violet goby would appreciate the shadowy, protected area. Then maybe add a sculpted ramp against the rear wall of the tank - all the way up to the beach, so if the crabs or mudskippers end up in deeper water they can more easily climb back to the surface.
<Now you're talking! Another idea is to let the return flow from a pump let out water over the ramp as a spillway. Several advantages: natural-looking, grows some useful algae, diffuses laminar flow, adds interesting movement
for the animals, will cause some evaporation which is probably desirable in this case...humidity.>
I could even sculpt a permeable underwater lip at the edge of the shallows to discourage them from getting in trouble. Add emergent plant stalks, root-like structures and floating plants along the edge to keep the larger fish at a distance to make the mudskippers more comfortable.
<As is the case in nature...animals who can simply avoid others when they desire are calmer, healthier.>
Then for the four eye fish, build a second ledge all the way across the back wall of the tank with a narrow land area that slopes into the water and then flattens out. Put plants on the land, and add some roots and floating plants at the edge of the underwater ledge to create a secure feeling area where the four eye fish can beach themselves and rest. Would this work? I read somewhere that the resting area should be in the middle of the tank, but no explanation was given for why.
<Watch out for too many species-specific modifications that may not be desirable down the road and may be a bit of a Rube Goldberg device. Do you really need separate ledges and so on for two amphibious species? I can
tell you that in the wild, mud skippers are perfectly fine hanging out on large roots, plants hanging into the water, shells, broken wooden palettes, iron barrels.....you get the idea. As long as they have a way to get out of the water plus some sand to beach on, they are golden. Point being simply that you don't need several separate habitats in one tank. Try to boil it down to be as simple yet effective as possible. What is actually *strictly* needed? Then go from there.>
The fringe of plants along the back and edge can be where I release insects for the archers to shoot at.
On the bottom create some caves & whatnot for the violet goby to dig & hang out in.
Let the blue leg crabs be the clean up crew on the bottom.
<Likely will need tens of these but they will be very interesting to watch and add a lot visually.>
I figure I'll use fake plants because of the high salinity and I don't want to constantly have to trim them in such a
deep tank.
<Ah well that changes a lot but at least consider mosses and at least a few contained/potted live plants. Artificial vines hung about would add a lot.
Also java ferns are easy. I will direct this also to the pond crew here at WWM who are past masters on that subject. See also http://www.wetwebmedia.com/ca/volume_4/v4i2/brackish%20systems/brackish.htm 
and one of my favorites http://www.wetwebmedia.com/mangrovetrees.htm.
My main concerns are preventing anyone from getting munched or drowning and providing a healthy and appropriate environment for all of the critters.
<Those are the main things to keep in mind, or course. I'd add "maintenance that's easy to keep up" and "everybody gets good nutrition" and all bases are covered, I'd say.>
I'd appreciate any advice.
Thank you!
Meghan
<NP and keep us posted!>
Big brackish tank - livestock selection & build     /Neale        4/17/17

Hi!
I've written to you several times and have always gotten great advice!
Thank you!
<Most welcome.>
I have a violet dragon goby that I want to build a big tank for, but I also want to create something really special and have some ideas I want to run past you.
<Cool.>
I'm going to build a huge plywood & glass aquarium - 8 ft long, 4 ft wide, and 4 ft deep. I only want to fill it to a depth of about 30 inches so I can make it into a palladarium style tank with above water plants along the back & sides. If my calculations are right, it will hold about 350 gallons of water.
<The mind boggles!>
My dream is to use it to house some unusual brackish aquatic critters. SG 1.010 to 1.012. Temp in the mid to high 70's. Use a protein skimmer and sump for filtration.
<Understood.>
My ideal stock list is as follows:
6+ Indian mudskippers (P. novemradiatus)
3+ fiddler crabs (whichever I can get)
6 banded archer fish (T. jaculatrix)
1 violet dragon goby (G. broussonnetii)
8+ four eye fish (whichever I can get my hands on)
12+ blue leg hermit crabs (C. tricolor)
<Some interesting ideas there. But...>
I have been researching this combo and have run into stern advice against putting many of these together, including on wet web media. But it seemed to me many of the issues revolved around too little space or the large fish
making the mudskippers reticent to enter the water.
<Correct. It may be possible in giant tanks -- I've seen large Mudskippers, probably West African Mudskippers, combined with Scats and Monos at the London Aquarium, for example -- but those Mudskippers are the length of
your forearm, and much bolder than most other species.>
If I can solve these problems they all seem to need the same kind of temperatures, do well in similar salinities, etc. If I can pull it off, it would be one heck of a tank!
<I'd say!>
I've been thinking about how to build an environment where they will all feel comfortable, and my idea is as follows:
On one side of the tank build a shallow area where the water is only a few inches deep (against the front of the tank), that then slopes up to a sandy land area (against the back) for the mudskippers & fiddler crabs. Put some plants & rocks/caves along the back of this beach. On the side of the shallow water & beach have a steep slope into deeper water. I'm debating how to build this slope & shallows/beach. I'm thinking a "false bottom" like you see in dart frog vivariums. Basically a hallow, permeable support structure for drainage with a circulation pump underneath. Wrap it with fiberglass screen and put the sand/gravel substrate on top.
<Makes sense, and the Mudskippers would be happy using a pool of water to bathe in, while avoiding another part of the set-up with bigger fish in it.>
I could completely enclose the underwater area beneath (and hide the heater, pumps, etc here).
Or I could make it open, like an underwater ledge or overhang. Use disguised pillars to support it. I bet the violet goby would appreciate the shadowy, protected area. Then maybe add a sculpted ramp against the rear wall of the tank - all the way up to the beach, so if the crabs or mudskippers end up in deeper water they can more easily climb back to the surface.
I could even sculpt a permeable underwater lip at the edge of the shallows to discourage them from getting in trouble. Add emergent plant stalks, root-like structures and floating plants along the edge to keep the larger fish at a distance to make the mudskippers more comfortable.
<All sounds very imaginative.>
Then for the four eye fish, build a second ledge all the way across the back wall of the tank with a narrow land area that slopes into the water and then flattens out. Put plants on the land, and add some roots and floating plants at the edge of the underwater ledge to create a secure feeling area where the four eye fish can beach themselves and rest. Would this work? I read somewhere that the resting area should be in the middle of the tank, but no explanation was given for why.
<It's simply easier in "box" tanks. Anableps will rest on anything flat, and in the wild, that'd be the "beach" part of the river or mangrove.>
The fringe of plants along the back and edge can be where I release insects for the archers to shoot at.
On the bottom create some caves & whatnot for the violet goby to dig & hang out in.
Let the blue leg crabs be the clean up crew on the bottom.
I figure I'll use fake plants because of the high salinity and I don't want to constantly have to trim them in such a deep tank.
<Agreed, unless you use true saltwater plants, such as mangroves or even seagrasses, both of which *can* be grown in tanks, though they are demanding.>
My main concerns are preventing anyone from getting munched or drowning and providing a healthy and appropriate environment for all of the critters.
<Yes.>
I'd appreciate any advice.
<Archers are carnivores that will take anything they can swallow. Toxotes microlepis is the smallest brackish water one, and ideal for this set-up because you can keep several (they can be bullies) without needing a huge volume of water or worrying about carnivory too much. Mudskippers will eat bite-sized crabs, so be careful combining them. I'd probably add some Mollies simply for algae control, but there are some brackish water Nerites out there that'd do an even better job. I don't personally recommend mixing Anableps with anything bigger or more aggressive than they are because they're super-nervous animals prone to miscarriages when stressed. I think Violet Gobies, Mudskippers, crabs, and perhaps Mollies would be fine, but the Archers might be a bit much for them unless the Anableps were a good size. Do also look at true Green Chromides (Etroplus suratensis) when you get a chance. Gorgeous schooling fish, and quite peaceful. They get along well with Archers, Monos, etc.>
Thank you!
Meghan
<Cheers, Neale.>
Re: Big brackish tank - livestock selection & build      4/19/17

Hi Neal,
Thank you for your reply!
<Welcome.>
I realized I got the gallons wrong for the tank. Filled to 30 inches it will hold almost 600 gallons, not 350 like I stated before. So I have more water to work with!
<Indeed.>
It sounds like the Anableps are much more nervous than I thought. I don't want them to be miserable.
<I doubt they will be miserable, but they are nervous. In the wild they occupy a habitat where fish are extremely vulnerable to predators. Little depth of water to hide from birds, but at the same time escaping from predatory fish is difficult because if they go the wrong way they can end up on dry land. So Anableps have those marvelous eyes that allow them to see predators above AND below the waterline, and alongside that, behaviours
that mean they react very quickly to anything unusual or risky. They work best on their own, or possibly alongside other shallow water specialists, such as Mollies.>
I really want the archers, I've dreamed about them since I first saw a nature special as a little girl. So I will scratch the four eye fish off of the list.
<Understood. Or alternatively, if the tank is huge, divided it into two halves, with a rocky barrier in the middle for the Mudskippers. If the Archers and Anableps are in separate halves, while the dry land bit is decorated to look like a seashore or mangrove, the tank would work nicely AND look pretty cool!>
Can the Toxotes microlepis (hope I spelled that right) handle water with an SG of 1.010 - 1.012? I think I read somewhere they are best at very low salinity.
<Correct; I'd be going for SG 1.005, which is fine for almost all the common brackish species; Anableps, Mollies, Mudskippers, Chromides; etc.>
If they can, I'd love to use the smaller species of archer fish - I could use more of them and I think a school of 12+ would be stunning!
<Quite so. In groups they're a lot more docile and well behaved. Singletons are safe but nervous, while twos and threes tend to be bullies towards each other.>
Those green Chromides are gorgeous! I'd love to include them but have one concern: my violet goby is a slow eater and often backs off of food if there are very boisterous, persistent fish at the food. I had him in a tank
with 8 Sailfin Molly adults and they drove him away from the food so much that I moved them because the goby was getting thin.
<Understood. Chromides and Archers mix very well, eating different foods; the Chromides being more omnivores with a taste for plant foods, while the Archers are strict carnivores that feed from the surface. I'd expect the
Archers and Violet Goby to work well too, since the Archers won't feed much from the bottom, and aren't well adapted to feeding on tiny plankton like brine shrimp that Violet Gobies love.>
Do you think the green Chromides would present the same problem?
<Possibly, since the Green Chromides will happily consume foods from the bottom as well as brine shrimp.>
I really would like to have some kind of mid water fish, but haven't found any I'm sure about.
<If this tank was divided into two, as suggested above, the Violet Goby could be kept with small things like Guppies, and probably Orange Chromides, a dwarf species that shouldn't pose much threat to an adult Violet Goby. On the other half could be the Archers, Green Chromides and Mollies, plus anything like a Silver Scat that took your fancy.>
Thank you!
- Meghan
<Cheers, Neale.>

Gold dust eel... Non-FW moray        4/11/17
Hi there,
<Winnie>
I am very lost. My first time to have a gold dust eel. I'm not sure what's happening to it. Pls help me.. what should I do..
<? Need data... is this fish being kept in brackish conditions? Water quality test results? READ here:
http://www.wetwebmedia.com/fwsubwebindex/fwmorayart.htm
and the linked files above (FAQs); re systems, feeding... Disease. Bob Fenner>

Gold dust eel /Neale        4/12/17
Hi there,
I am very lost. My first time to have a gold dust eel. I'm not sure what's happening to it. Pls help me.. what should I do..
<Hello Winnie. Judging by the Stingray, your Gold Dust Eel is in a freshwater aquarium. He WILL NOT LIVE in a freshwater aquarium. These are brackish to marine species. Given your obvious expertise if you're keeping
Stingrays, let me immediately direct you to some reading:
http://www.wetwebmedia.com/fwsubwebindex/fwmorayart.htm
I'd also be dosing with an antibiotic, but once in brackish or marine conditions, your Moray has a good chance of recovery. Unfortunately, in freshwater tanks they INVARIABLY stop feeding eventually, and over time, lose their vitality and energy, eventually dying from a bacterial infection, osmotic stress, starvation, or some combination of these. The precise salinity doesn't matter too much, but 25-50% normal marine is about right, i.e., about SG 1.005 to 1.010. Cheers, Neale.>

Brackish frogfish? 4/10/1
Hello,
<Meghan>
I have an aquarium (30" x 25" x 18" -- footprint size 30 x 18) that holds about 58 gallons.
I'm starting to research possible inhabitants. Is there a brackish frogfish that would be appropriate for it? All I'm finding are in the realm
of 12" except a few around 9" that appear to be fully marine??
<As far as I'm aware, all Antennariids are marine, none brackish long term.
Am asking Neale Monks here for his more informed input. Bob Fenner>
Thanks!
Meghan
Brackish frogfish? /Neale
 4/10/1
Hello,
I have an aquarium (30" x 25" x 18" -- footprint size 30 x 18) that holds about 58 gallons.
I'm starting to research possible inhabitants. Is there a brackish frogfish that would be appropriate for it? All I'm finding are in the realm of 12" except a few around 9" that appear to be fully marine??
Thanks!
Meghan
<<Hello Meghan. There *is* a brackish water Antennariidae, specifically Antennarius biocellatus, though it isn't widely traded. Fishbase describes an adult length of 14 cm, or about 6 inches in old money.
http://www.fishbase.org/summary/11113
On the other hand, there are several brackish water Waspfish, Toadfish and other stealth predators that are traded and might fit the bill nicely.
These include:
Neovespicula depressifrons, a very active grouper-like Waspfish;
Notesthes robusta, a relatively inactive stonefish-like predator;
Batrachomoeus trispinosus, one of several brackish water frogfish imported periodically.
There's also a sleeper goby, Butis butis, that occupies a similar niche and has been very widely traded at times under the 'Crazy Fish' name, which relates to its tendency to lurk at odd angles, even upside down, almost
anywhere in the tank.
If any of these are of interest, write back for more. Cheers, Neale.>>

Columbian catfish with stomach bulge      4/7/17
Hello, I have a 120 gallon tank with 2 Columbian catfish about 8 inches long.
<Nice size tank for these brackish/marine catfish!>
I also have 2 rainbow fish, an albino rainbow shark, 3 baby Bala sharks and a Gourami.
<Bit confused why you're keeping your Colombian Shark with freshwater fish.
You do realise that Colombian Sharks will not be healthy (or happy) in freshwater? Adding enough salt to keep the catfish happy will kill the freshwater species. Furthermore, anything bite-sized is potential food.

While not aggressive or nippy, these catfish *are* carnivores.>
1 of the catfish has developed a lump in its stomach overnight. He is eating and swimming alright. I feed him algae pellets, flakes, bloodworms, and shrimp pellets. Everyone else in the tank looks fine. I'll attach a picture. Please let me know if there is any way to help him.
<Time. Predatory catfish are prone to overeating if you let them. Best kept with fast-moving brackish or marine fish that eat different things. Monos or Damselfish, for example. These catfish don't need feeding every day, or at least, not heavy feeding every day. They will regurgitate excess food if overfed, polluting the water.>
Thank you for your help,
Jess
<Will direct you to some urgent reading...
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/ariidae.html
Easy catfish for communities of medium sized brackish and marine species, but frequently stressed (and ultimately killed) by poor care. Cheers, Neale.>

To: Brackish INDEX;

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: