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FAQs on Knight Gobies

Related Articles: Fresh to Brackish Gobioid Fishes

Related FAQs: Fresh and Brackish Gobioids, Brackish Water Fishes in General

ATTN: Neale: South American Puffers & Knight Gobies  -12/11/08 Hello Neale (or other crew teammate): It has been a while -- I hope you are well. In the past, I have discussed South American Puffers with you, and although my family and I are in love with them, we still don't have any in our home. I have created a plan for a new aquarium, (which will be the tenth one in our house). I would sure appreciate it if I could run my plan by you, to see if you think it's a "sound" plan, and to get an additional idea or two from you. My plan is to set up a new 65 gallon aquarium, with dimensions of 36"x18"x24". I would like to stock it with South American Puffers and Knight Goby(ies). Based upon what I've read on W.W.M. and heard from you, I believe the S.A.P.'s can be healthy in freshwater or slightly brackish, and the Knight Gobies would do *best* in slightly brackish water, so I think it would be best to run it with specific gravity of 1.03. Do you agree? I have very hard water with a ph of 7.8. So the next question is: Can I use that as it is, or would I would need to "temper" it with some of my R.O. water? I would prefer to use straight tap water, if it would work out okay. Could you please make a suggestion for a good/healthy number of each species, to keep in this tank? Are there any bottom dwellers for this set of circumstances? Finally, would 10-12 times/hour be a healthy turnover rate for my filtration system? Thank you for your time and attention, and for what you do. I'm studying and learning all the time. Cheers, Jake. <Hi Jake. In terms of salinity, both Colomesus as Stigmatogobius will be fine at SG 1.003. The hard water will be fine, indeed better than fine. Certainly don't need to use RO water unless your local water has a lot of nitrate or ammonia in it. Colomesus can be kept singly, but is much less nervous kept in groups, ideally three or more. Knight gobies are territorial but work great in groups, even pairs, provided they aren't overcrowded. Now, in terms of social behaviour, SAPs can be a bit on the nippy side, and Gobies are precisely the sorts of fish prone to nipping, what with their long fins and slow swimming speed. This isn't to say Colomesus are wildly unmanageable nippers, far from it, but some specimens are persistent nippers and this can cause not just stress but also make the victim prone to Finrot. For bottom dwellers, I'd recommend perhaps catfish, such as Hoplosternum littorale or one of the Asian Mystus catfish such as Mystus vittatus, Mystus aff. gulio or Mystus wolffii, all peaceful schooling predators that get to about 20 cm in length. Brackish water fish tend to enjoy fast turnover rates, but I'd take care not to go berserk with the water flow. Make sure there's some slower pockets where fish can rest. Large rocks and careful use of spray bars/outflow pipes should take care of this. Cheers, Neale.>

Breeding Stigmatogobius sadanundio  2/10/09 Hello, I would like to know if there is a breeding report available regarding the knight goby. My search on the internet was not really successful so I thought I might give it a try and ask you. Our group of 7 gobies spawn readily but so far I had no success raising the fry. Best regards and thanks in advance Heiko <Hello Heiko. Yes, this species has been bred in aquaria, but not often. Like a lot of gobies, the spawning part comes easily to these fish. Broods consist of up to 1000 eggs, laid inside a cave and defended by both parents. The eggs hatch after 48 hours, and the fry will need tiny live foods (infusoria, rotifers, Cyclops nauplii). Brine shrimp nauplii are too large for them. Because of this, it is really only practical to remove the eggs after spawning, and put them in another tank where you can feed them. If you can find it (e.g., via a library) the November 1987 TFH magazine has an article called 'Breeding the knight goby, Stigmatogobius sadanundio'. May well be worth a look. Cheers, Neale.>

Companions for a Knight Goby -- 06/26/07 Hello, <Greetings.> A few years ago I made a mistake by purchasing a fish before doing my homework on it (I've learned my lesson). I purchased a knight goby from my LFS. They claimed he would do well in my 65gal freshwater tank, and well, he definitely has. He's the most aggressive eater in the entire tank, and he has a nice round belly. I've since learned that he would do much better in a brackish tank, but I'm unfortunately unable to convert the tank over due to his tank mates. We do have very hard water though, and I've read they can do very well in freshwater as long as the water is fairly hard. <Knight gobies are unambiguously better in brackish water. Success in freshwater aquaria is variable. pH and hardness are certainly factors. Water quality is probably also important: brackish water fish are super-sensitive to things like nitrate and nitrite in freshwater conditions despite being hard as nails when kept in brackish water conditions. But the bottom line is when kept in freshwater they just don't last as long as when kept in brackish water. The required amount of salt is not great: SG 1.003-1.005 will do.> Anyway, my problem is, he keeps eating the majority of his tank mates. He seems to enjoy the company of the clown loaches, but he's eaten all my neon tetras, Danios and all but one white cloud. The Rasboras and the clown Pleco are apparently too big for him to eat, so he doesn't bother them much. He even ate the fins off a Sailfin molly, and eventually killed it. No one around here will take the goby, not that I really want to get rid of him anyway, because he is very beautiful. What other fish can I put in with him? <Knight gobies are piscivores, pure and simple. Small fish are food. They mix well with sturdy brackish water species such as Figure-8 puffers, Orange Chromides, sleeper gobies of various types, scats, monos, and so on. If I was keeping him with freshwater fish, I'd be choosing fast-moving salt-tolerant species such as olive and Ticto barbs, Australian rainbowfish, Madagascar rainbowfish, glassfish and so on. These at least would allow you to add a little salt if the goby comes down with Finrot and fungus (both very common when brackish fish are kept in freshwater). Best of all they are kept with their own kind so that you can see their interesting social behaviour. They also spawn quite readily, though rearing the fry is not easy (and probably impossible in freshwater). Thank you for your assistance. -Jill <Hope this helps. Neale>

Post-mortem on new knight goby Hi guys, <hello, dear... Anthony Calfo still duct taped to a chair answering e-mail. Bob won't let us visit the forum or any other page on the WWM site <wink>> I got a new male knight goby last Thursday. I picked the male that looked the best of a not-so-great lot. He went into a 5.5g QT tank, with new water and an old/active sponge filter. He didn't eat, despite being offered all of the usual goby favorites (bloodworms, blackworms, mysis shrimp, squid, etc). His belly became sunken after a couple of days. His breathing became more very rapid and labored. Then last night I noticed red spots under his eyes. He was also darting around the tank. I did a 50% water change but did not see any improvement. This morning he was gone...as in jumped out. (I couldn't find him. I'd planned on putting a cover on the tank last night, but forgot. Doh!) My thoughts are that his symptoms may have been signs of cyanide poisoning.  The few bits that I found on WWM mentioned not eating and good color. And knight gobies are found in the Philippines and Indonesia, places where they still use cyanide. Any thoughts? <unlikely cyanide... at least with this species IMO. More likely the culmination of duress from a long and perhaps mishandled chain of custody on importation. I'm thinking the little fellow was indeed close to death before you even bought him. Many such fish suffer more than a week of fasting on import> (In the silver lining department, this has me more determined to figure out how to raise knight goby fry. The female in the 30g spawned last week, but they didn't like the shells in the tank so the eggs became a fish treat. I've put a small barnacle shell in the tank, so maybe next time they'll take that.)--Ananda <outstanding! best regards in this endeavor. We have a local grand master breeder who favors blennies and gobies if you ever want to look her up. Her name is Sallie Boggs and one way you can reach her is through our society mailer at members@pmas.org Anthony>

Knight Gobies I have been keeping tropical fish for 7 years. My local pet shop has just received a stock of Knight/Night (I am not sure of the spelling) Gobies. I was just wondering how difficult it is to keep these fish? Some questions that come to mind are: 1. What sort of temperament are they, aggressive, peaceful etc.? 2. What do they feed on? 3. Are they fussy about pH and water temperature? I have currently got a 50Lt tank, with the following fish: 1. 1 x pair of swords 2. 1 x Redtail shark 3. 1 x Plecostomus 4. 4 x Corys 5. 2 x Dwarf Gouramis 6. 2 x Guppies 7. 2 x Sunset platies Please let me know whether getting a pair of Gobies would be a good idea, indicating the answers to the above questions and any other items of importance. Thanks a million, Ronald. <Hey Ronald, these Gobies would be better placed in peaceful or dedicated brackish water system.  There is some more information available here http://www.wetwebmedia.com/BrackishSubWebIndex/bracgobioids.htm and on fishbase.org, you will want to search for Stigmatogobius sadanundio.  A search on Google.com should also provide some good information.  Best Regards, Gage>

Knight Goby article Hi Bob, <Ananda> After a couple of false starts, I'm finally actually getting somewhere with this article. I found the "automagic breeder report article writer" on the Greater Chicago Cichlid Assoc. web page (http://www.gcca.net/infochest/auto-magic-writer.htm), started with that, and now I'm adding text to the "outline" it generated. I'm wondering if I'm taking the right sort of tone for this sort of article... this is *so* different from technical writing. Would you mind reading over my first page (of the first draft) and letting me know if I'm on track or headed off into the weeds?  thanks, Ananda <Looks good to me. Bob> Breeding the Knight Goby (Stigmatogobius sadanundio) by Ananda Stevens I remember the first time I saw a knight goby. I had recently started a brackish tank, and was looking for my first fish. There were several tanks in the office, and while I'd wanted a tank of my own, I had to do something different. I was bewildered by the variety of freshwater fish. But the variety of brackish fish available is much smaller, even in the Chicago area. I'd decided to do a brackish tank both to do something different from the crowd and to narrow my fish choices. Then I saw the knight goby, and knew I had to have one in my tank.  The knight goby, also called the fan-dancer goby, is a small fish, attaining perhaps 3.5" in its native habitat. It has a mostly-beige body, with black spots on the body and some of the fins. Perhaps the most striking feature is the first dorsal fin, with its spiky rays and iridescent blue dot. The pectoral fins are clear, and, as a true goby, the pelvic fins are fused and form a cup-shape. This fused fin enables the goby to perch on surfaces that are nearly vertical, from which it watches its surroundings. That, coupled with the fish's swimming habit of short spurts, make this a fun fish to watch.  The knight goby, whose Latin name is Stigmatogobius sadanundio, is an egg layer native to the India, Thailand, Malaysia and Indonesia, according to Fishbase.org. The fish has also been reported in Bangladesh and Sri Lanka. The climate in these locations is tropical, with water temperatures in the 70s (20 -- 26°C). The native waters for this fish have a pH of 7-8, and a dH of 9 to 19. The fish is freshwater to brackish, and is found in both freshwater and brackish tanks in stores in the Chicago area. I believe that the fish is commonly kept in brackish tanks partly because of the hardness range the fish prefers. I have kept the fish in freshwater for many months with out any apparent ill effects; however, the water where I live is very hard, with a dH of around 12 and a pH of 7.6-7.8 out of the tap. However, in an area with soft water, or in an office with softened water, I would definitely keep this fish in a brackish setup.  I later bought a second goby from a different fish store. I picked out the one with the darkest fins, not realizing at the time that the fish was showing off its breeding dress. This is one of the few ways to distinguish the males from the nearly-identical looking females. Both males and females achieve a size of around 3.5" (9cm) and are beige with numerous black spots, with several spiky rays and an iridescent blue spot on the first dorsal. The males have a longer second dorsal than the females, though this can be difficult to spot in immature specimens. In a mature male, the second dorsal will very nearly touch the caudal (tail) fin; in a mature female, the fin is somewhat shorter. Another certain way to determine the gender of the fish is when the female is egg-bound. The female develops a shape reminiscent of a tadpole, with a protruding ovipositor that has a rounded end. While the gonopodia of the males are reported to be less rounded, I have never seen the two to compare them side by side. The male may also get a slight occipital lump while in breeding dress, though this may be so slight as to be useless as a gender differentiator. 

Night Gobies? Actually "Knight" Gobies - Stigmatogobius sadanundio - 11/09/2005 Hi. I was directed to your website during my search for night gobies.  <Mm, actually, it's knight gobies.... as in soldier, not as in after dark. This is the trouble with common names. Try Stigmatogobius sadanundio .> I have a pair of night gobies, and they have just recently laid eggs. Is there anything that I should know about the gobies?  <Oh, sure.... I would recommend browsing through our FAQs  http://www.wetwebmedia.com/BrackishSubWebIndex/bracgobifaqs.htm  and posting in our forums  http://www.wetwebfotos.com/talk  - past Crewmember/forum member Ananda has bred these, and may have some pointers for you.> I have separated the gobies from the eggs, <Mm, I do believe Daddy is useful to the eggs (prior to hatching).... without him, some form of circulation will be necessary.... You might try coupling the "correct" common name (if ever there were such a thing) with "breeding" in a Google search.> along with the other fish that were in the tank. If you could throw me some pointers I would REALLY appreciate it! It seems that no one knows about night gobies, and there seems to be nothing online about them.  <No, but you'll find much on knight gobies (grin).> Thanks so much for your time. -Lindsey

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