FW Ray Nutr Dis F

FAQs on Freshwater Stingray Nutritional Disease

FAQs on FW Stingray Disease: FW Stingray Disease 1, FW Stingray Disease 2, FW Stingray Disease 3, FW Stingray Disease 4,
FAQs on FW Stingray Disease by Category: Diagnosis, Environment, Trauma, Infectious (Virus, Bacterial, Fungal), Parasitic, Social, Treatments

Related Articles: Freshwater Stingrays,

Avoid freshwater "feeders".... vectors of pathogens, Thiaminase instigators... Ditto w/ Blood, aka Sewer Worm larvae ("worms")

Skinny Stingray 4/21/18
My motoro stingray is a pretty active stingray but parameters in the tank are normal (no nitrates, nitrites, ph levels are normal)
<I would prefer the values rather than a statement! To recap, nitrite should be zero of course, and nitrate as low as practical, though zero nitrate is in practical terms very difficult to achieve. If you are honestly getting a zero reading for nitrate, I'd double-check you're using the test kit right, because a zero nitrate reading in a tank with a large,
predatory fish is so unlikely. While the precise pH value isn't critical, it should be stable and not too high, and ideally, hardness and pH would be towards the soft water end of their respective ranges; maybe 2-15 degrees dH, pH 6.5-7.5.>
and there is no chance of infection or parasites.
<How can be you be so sure? Even at the retailer there's some risk of exposure.>
There are constant water changes and filter changes with at least 25% changed. He is fed everyday or every other day with more food (this does not happen often, but there are issues that come up as they do in life, but not enough for there to be leftovers in the tank).
<Understood.>
He has been in our tank for over a year and a half and has been growing steadily, so we are pretty sure there is no stress, and as he has survived this long and continues to grow.
<I agree, this is promising.>
Our substrate is a soft gravel that My parents used years ago with another ray who lived a long life (obviously rinsed thoroughly with water).
<I am sure you're aware of the debate surrounding the use of substrates in ray aquaria. There are arguments in favour of soft sand substrates, and arguments in favour of no substrate at all. I wouldn't say it comes down to personal taste, but the latter approach is perhaps easier and safer.>
He is a very happy ray in all searching through gravel, finding Blackworms, swimming around all normal ray things. My problem is that he is too skinny.
He is fed a good diet of shrimp, Blackworms and live fish (who have been quarantined by fish store for at least a month usually more) but he will not gain weight.
<Live fish is already one major risk factor. Let's be clear, unless you're home-breeding thiaminase-free fish from parasite-free parents, then any live fish are dangerous. End of story. For a start, cyprinids (goldfish, minnows, and their relatives) contain thiaminase and simply should never be used as live food. No scientifically sound argument can be made in favour of using those types of fish, and store-bought "feeder" goldfish and minnows are simply parasite-bombs. If you've used those, then right there is one very probable reason for the ill-health of your Stingray. Thiaminase is an enzyme that breaks down thiamin (vitamin B1) and when used regularly the predatory fish can/will develop all sorts of vague, but potentially lethal, health issues. There's a BIG scientific literature out there on this subject, but let me direct you to Marco Lichtenberger's summary here at WWM, written specifically for aquarists:
http://www.wetwebmedia.com/ca/volume_6/volume_6_1/thiaminase.htm
Next up, the feeder fishes bought at pet stores will almost certainly have parasites of some sort in them, and quarantining them only means those parasites aren't killing the host fish. Get those feeders inside your predatory fish and things become more complicated. A goldfish might, for example, have a degree of resistance to a certain parasite because they evolved together over thousands if not millions of years, but South American Stingrays may never encountered parasites common in Eurasia, and would have no resistance at all to that parasite. Do you see the problem here? It's not a definite explanation, but the use of feeders is just such a wildly risky chance to take, that it is very difficult to rule them out. Given Stingrays aren't obligate fish-eaters in the wild, there's no real reason to feed them live fish anyway, and most if not all experienced Stingray keepers and breeders avoid them. Instead focus on invertebrates, particularly worms, as well as more mixed, vegetable-rich food items that offer vitamins and fibre. Gut-loaded earthworms and river shrimps are a good way to get vegetables into your Stingray! Alongside these, a good
quality Stingray pellets will help round out their diet, and arguably could make up their entire diet if you're on a budget.>
He also completely refuses to eat things like smelt, nightcrawlers and even wild caught shrimp (as in once he smells it on your hand he will not come near you the rest of feeding time he hates them that much) and we have tried countless times to introduce him to other foods.
<The golden rule with fish remains this: they'll eat when they're happy and healthy. If they're not eating, it usually means there's a problem. It's very rarely the food itself that's wrong, but something else. Could be water quality or chemistry, could be the lighting (Stingrays hate bright light), could be the tankmates, if any (Stingrays are best kept alone). But as we've discussed, there could be a deeper problem if live feeders have been used, especially goldfish or minnows. Nobody keeping a fish as valuable and as delicate as a Stingray should be giving them live feeder fish.>
We have even hidden some in the foods he does enjoy and he spits out the food he doesn't like once he figures out it is there.
<Classic food refusal.>
He is too skinny but as I said he is still growing outwards so he is still healthy but I hate seeing him so skinny.
<I would be thinking along the lines of internal parasites, if he "eats but stays thin" but I'd also be worried about thiamin deficiency.>
Are there any fattening foods that I can safely feed a ray?
<See above; your Stingray doesn't need more calories, but he does need his appetite back. You need to review that aspect, and act accordingly.>
I've seen people suggest clams, muscles, and worms.
<Clams are good. Mussels can be used sparingly -- again, they contain thiamine. Earthworms are good and safe; bloodworms and especially Tubifex worms substantially more risky, and best avoided.>
We can try other fish but I'm not sure how he will react. Any tips or suggestions will be much appreciated!
<Hope this helps. Cheers, Neale.>

motoro rays... Fdg., nutr. dis. 7/13/10
Greetings Crew,
I have two Male Motoro rays. They are about 10' disks now. Both have lived in a 1200 gal tank since they were 4" disk. They have a complete Life support system, reservoir, sand filter, chemical filter ,bio filter, R.O., UV sterilizer, chiller the works! I Back wash the system 2-3 times a week.
They live with discus and an Arowana and a few Blood Parrots they are in an aquarium we custom built in a local Casino. Within the last week they have slowly lost their appetites. They seem to have lost their desire to swim.
One has been bumping into walls and is now showing a lot of trauma to his disk. He swims upside down and has been puffing from the top. All my water tests are perfect.! They eat krill, bloodworms and any small schooling fish they can catch. I feel the bloods are taking advantage of them. Though the owner doesn't want to let them go! Ughh! To my question...I retrieved the Rays last night and isolated them in their own tank. I don't know what to treat them with. They are swimming about a little more today but the white (picking) areas look bad. And still not eating. Any and all suggestions are much requested.
Thank you
Ginger
<Hello Ginger. The reasons why Stingrays refuse food are varied. As you correctly surmise, environment is the commonest issue. So yes, checking water quality, water chemistry, and water temperature are all important.
Consider any possible toxins: paint fumes, insecticides, etc. Make sure no-one has been doing anything silly to these Stingrays like feeding them human food "treats". Next up, the use of feeder fish. This cannot be
stressed too strongly. If you have predatory fish and you want them to die, feed them feeder fish. Never, EVER use store-bought feeders.
http://www.wetwebmedia.com/fwsubwebindex/fdgfdrartneale.htm
Goldfish and Minnows are the worst because they not only contain parasites but they also contain large amounts of Thiaminase and fat, and used regularly will cause [a] vitamin B deficiency and [b] damage to the internal organs. Thiaminase is common in some types of seafood and fish, notably prawns, shrimps and mussels. Use Thiaminase-rich foods no more than once or twice a week, and all the rest of the meals must be Thiaminase-free foods. Until quite recently most aquarists had never heard of Thiaminase, but it is now reasonably clear that this is a major source of ill-health and premature mortality.
http://www.wetwebmedia.com/ca/volume_6/volume_6_1/thiaminase.htm
If you've been using feeders or not taking care of the Thiaminase issue, the damage may be done. A vet trained in handling cartilaginous fish may be able to offer some help, but otherwise there's little you can do. Next up, there's monotony. Stingrays need a varied die, and surprisingly, it needs to include some green foods for fibre. Cucumber, cooked peas and lettuce leaves are nibbled on by hungry Stingrays, and whether they're a major source of nutrients isn't clear, but their value as fibre does seem helpful. Zoos often create mixes with things liked cooked brown rice and carrots! If they won't take greens, then live earthworms are nearly as good, having guts filled with decaying leaves. Finally, there's harassment. Stingrays generally mix poorly with other fish, and Suckermouth catfish in particular can harass them. As for their injuries, if these are nothing worse than scratches, these should heal fine assuming water quality is good. There are no completely reliable medications for treating Stingrays, which is why avoidance of sickness is so important. Potamotrygon spp. tolerate salt quite well, at least for periods of a few weeks, so in some instances slightly saline water may be helpful for external parasites, but generally that isn't necessary. If the Stingray can recover, it will do under its own steam. Cheers, Neale.>
Re: motoro rays [RMF, any ideas on medications?] <<Furan cpd.s RMF>> 7/13/10
Thank you, unfortunately I lost one of them earlier today after writing to you. The other fellow is still struggling with himself. I have offered bloodworms twice to no avail. Is there no treatment to help the healing I could add to his tank?
<No. As stated, a vet who treats sharks and rays may be able to help, but adding "potions" as you'd do with regular fish won't have any positive effects at all. An antibiotic might be used safely, but you'll need to check with your vet or the manufacturer first.>
I have him now isolated in a 500 gallon holding tank. With a soft sandy bottom. The wounds are pretty much all white and some dark patchy areas on his upper side. Thank you for your time with me.
<As stated, if you have ever used feeder fish, you've basically thrown all your chances out of the window. Feeder fish are hands-down the single best way to kill predatory fish short of hitting them over the head with a priest. If you've offered Thiaminase-rich foods too often, again, the damage is already done. It really comes down to this: if water quality is excellent, and the internal organs haven't been damaged by Thiaminase or parasitised by the use of feeder fish, sick Stingrays can get better under their own steam. But if the damage is done, there's really nothing left but praying to the Fish Gods. Cheers, Neale.>

Possible Motoro Parasite/Feeding Frustrations (RMF, second opinion please) 3/10/09 Hello, <Hello Kyle,> Before I ask my question I think it's important to note that my 7 inch Motoro was purchased and acclimated 3 days ago, so he is still undergoing the typical acclimation stress (and the underside of his disk is reddish). Now that he has become more acclimated and begin scrounging for food, I noticed a small brown spot on the underside of his disk in the shape of a butterfly, with a little raised light-colored bump in the center of the spot. I have attached the best picture I was able to get of the spot (my ray swims fast on the glass), but I was wondering if this could be a parasite that hitched a ride on my ray; and if so, where can I find instruction to remove it as safely and stress-free as possible? <It isn't clear to me what this is, and I'm asking Bob for advice here.> <<Isn't clear to me either, but at largest amplification, cleaning up... and the position of this mark... it appears to be more of a "bruise" to me than anything else. Not parasitic. RMF>> In case it helps, my tank is registering nitrates at 5 PPM, with everything else at 0. I have a fine sand substrate and filtration to turn 10 times the volume of the tank. In addition, I was wondering about feeding. I have read and heard of stingrays on "feeding strikes" or "not accepting food" but mine seems to be very fickle about his food, neither accepting nor rejecting it in any predictable way. He's nearly always blowing the sand around looking for food, but if he does pick up a worm or small piece of raw shrimp, he will sometimes spit it out of his mouth even if he's accepted it from me greedily before... only then to further swim around the tank looking for something else to eat. One example is just an hour ago, I put half a live nightcrawler in there, and he sucked it out of my hand hungrily, then spat it out. For the next half hour he would gnaw at it, spit it out and then swim around the tank, eventually eating it. So far, I have tried bloodworms, red wigglers, nightcrawlers, and ground raw shrimp; all which have been accepted and rejected in an unpredictable fashion. Thank you for your time and advice, I look forward to hearing back from you. Kyle <While these fish are finicky, one key thing about their appetite is stress. So your Stingray may simply be settling in and not ready to feed consistently. But it could equally easy be an issue with water quality or water chemistry stability, so think about these factors too. Review tankmates, and see if there's anything that might be stressing the Stingray. Take care not to overfeed; when we bring home a new fish, it's tempting to keep feeding the new fish to check it's healthy and happy. Cheers, Neale.><<Totally in agreement. RMF>>

Re: More: re: Possible Motoro Parasite/Feeding Frustrations (RMF, second opinion please) 3/12/2009
Hi, guys- thank you for your help and quick responses. I tried to see what might be stressing him, but the water seems stable,
<"Seems"? You don't get this latitude with stingrays; the water MUST be stable. Keeping them in huge tanks helps, as does performing very regular (ideally, daily) water changes so that background acidification doesn't get
a chance to occur. The carbonate hardness should be reasonably high; while soft water fish in the wild, pH variation is much more harmful than moderately hard water.>
he has no tank buddies, and the temp is kept at 80 degrees.
<Too warm. The usual 25 C/77 F is ample for these and indeed most Amazon Basin fish (with a few exceptions, like fish from the Xingu River which do like things a bit warmer). The warmer the water, the more active a Ray will become, but the cost of higher metabolism is increased demand for oxygen and a heavier workload on the filter. Unless you're breeding fish, it's usually best to keep them at the cooler end of their preference range. Not cold, by any means, but verify their preferred temperature range from Fishbase or similar, and work from there.>
And I have decided to call that brown spot a "beauty mark" and will continue to do so until the moment (if and when) it appears to be a trouble spot.
<OK.>
I have noticed since my e-mail before that there is a small amount of regularity in his feeding. He seems to have no trouble accepting one nightcrawler in the morning and evening, but anything after that he will not eat. His belly also appears to be getting less and less red each day (although this may partly be wishful thinking more so than objective observation)... so I am taking that as a sign that he's getting better acclimated.
<Yes.>
It's still a little weird to me that he is spending a lot of time blowing sand around looking for food, but won't eat much, and then spends a lot of time swimming in the same pattern around the glass.
<What kind of sand are you using? Anything likely to irritate? Many aquarium sands are too sharp for benthic fish. If in doubt, plain vanilla "smooth" silica sand is fine.>
I actually had to put a book on the corner of my tank, because it appears as though he keeps trying to jump out that corner (I wont worry about a tank cover until I see him trying to jump out anywhere else).
<Normal behaviour if they're stressed. Again, this may stop if the fish settles in, but if it persists, then review conditions and act accordingly.
The usual problems with Stingrays are insufficient water volume,
insufficient filtration (water turnover), and unsteady water chemistry.>
Is it possible, since the tank at the store was decently decorated, that adding some small decorations would help him with his level of comfort, or are rays not as concerned with decor as some other fish?
<Wild fish hide by digging into the sand. Floating plants will certainly be welcomed for the shade they provide, but bogwood, rocks, etc are redundant and indeed undesirable if they trap dirt.>
Well, it seems this 'thank you' has turned into a "holiday mailer" so I will cut it off here. Thanks again for all your help,
`Kyle
<Cheers, Neale.><<Excellent resp. Neale... content, format wise... Have nothing further to add. BobF>>

Re: More: re: Possible Motoro Parasite/Feeding Frustrations (RMF, second opinion please) 3/12/2009
With regard to the substrate, it is a very fine sand. It may be that the granules, although small, are sharp if the sand is an issue.
<Feel the sand; smooth sand feels velvety, sharp sand feels otherwise.>
If upon further investigation of his habits, I determine that the substrate
is causing him irritation, would adding a small layer of a different, smoother sand work?
<Replace all the old sand with smooth sand. No point being cheap here; for the sake of a few dollars' worth of sand, you could end up with an infected Stingray. Dump the old sand in the garden. Mixed with soil, it helps improve drainage. So no waste.>
I am trying to avoid ripping out the bio-colonies in the sand by replacing the substrate altogether.
<No useful bacteria in the sand.>
Perhaps replacing the substrate over time, bit by bit? What would work best for that?
<Replace all.>
Now that I read what I wrote, I realized "seems" doesn't fit what I am observing with the water. That was my way of saying I am checking it daily, levels are fine, so unless there are fluctuations in the water source here in ways I can't measure, then water quality isn't the issue. So, in this case, seems=if something's wrong, it's going to catch me off guard.
<Right, I see.>
Sorry to be such a bother with all these questions and trouble. This is (quite obviously) my first ray, so I am erring on the side of cautiousness, which may not be an err in ray-keeping at all.
<Very wise indeed. Do invest in one of the several books on the topic. Some are inexpensive (like the Barron's one) and will save much money in the long term.>
`Kyle
<Cheers, Neale.>

Re: More: re: Possible Motoro Parasite/Feeding Frustrations (RMF, second opinion please) 3/15/09
I thank you again for your assistance. I don't know what the problem could be anymore, because the substrate feels soft and smooth to me, not scratchy like some sands I have used.
<Well, that's good.>
Water quality is fine and I have been changing at least 10 percent of the water every day.
<Define "fine". The thing with Stingrays is that 99 times out of 100, problems are down to water quality and/or chemistry issues. Obviously you need zero levels of ammonia and nitrite, but nitrate also needs to be very low, realistically as close to zero as is practical. The water chemistry should be stable; ideally soft and slightly acidic, but regardless of the hardness level, the pH should be rock steady.>
He simply is refusing to eat anymore.
<Was he feeding at the aquarium shop? What were they feeding him? For all the usual reasons, I'd never recommend buying a specimen that was fed feeder fish, particularly goldfish. But if it was consuming earthworms and other safe foods, it should be in good shape. Assuming he's eating something, and has hitherto taken a meal every couple of days, he can be "starved" for a week or more without problems. But the flip side is this:
Stingrays tend to be greedy feeders for things like earthworms and live river shrimp when happy, but refuse to feed point blank when stressed in some way.>
There seems to be a connection between me coming into the room or near the tank to do maintenance and him going to hide in the substrate.
<Some degree of nervousness is common initially after purchase, but fish generally settle down within a few days to a week. Do review the general environment though: loud televisions, slamming doors, busy corridors can all make fish much more nervous than otherwise.>
I am honestly getting a little frustrated with this guy; I really only try to feed him morning and evening. Maybe I just need clarification on what people mean when they say "feeding strike." Obviously, there's an element of non-eating, but if he's on such a "strike" then why does he spend the whole day searching for food?
<To some degree you must dissociate foraging behaviour with actual feeding; fish will instinctively forage for food all through their day (or night) activity cycle. They don't need to be eating constantly though, and simply because they're foraging doesn't mean they need to be fed.>
Most times, he finds what I give him and greedily begins to suck it down but then spits it out or leaves it, and then goes to hide.
<Maybe he doesn't like it? What are you offering?>
I'm afraid I am going to lose this guy, and it just feels wrong because I have been doing everything that I have been told either by people or by my very deep research (I did get the Barron's book before I bought him).
<My gut feeling here is this: [1] Review environmental/water conditions; [2] Double check them! [3] Turn the lights out for the next few days. [4] Don't feed him for at least 3 days. [5] Get some nice, fat, juicy
earthworms and offer one of them late in the evening on the fourth day.>
I am sorry there wasn't much of a question in this e-mail. I guess I figured I may have said something about his behavior that may show something we haven't noticed before.
`Kyle
<Cheers, Neale.><<I do agree with your probable prognoses... advice Neale... If none of these can be found to be at fault, when-corrected, restore this fish to feeding, I would return it to the store. BobF>>

Re: More: re: Possible Motoro Parasite/Feeding Frustrations (RMF, second opinion please) 3/15/09
Hm... thank you for the distinction between searching and hungriness. That has helped me a little. When I bought this one, I was actually in the LFS looking at another stingray that they tried to feed an earthworm and he didn't go for it, but this guy came speeding up to it and started to eat it down; he looked healthy and obviously hungry so I got him instead.
<An excellent way to choose Stingrays.>
He did have a little trouble eating the whole thing because he's a smaller ray still, but he did (and still does) get the whole nightcrawler down eventually. I have also tried breaking the worms in half or 3 parts but he loses interest or only eats the front-worm part. Thank the Lord I care for an African clawed frog who will eat what my ray rejects. Other foods I used are glass shrimp and raw supermarket shrimp, and red wigglers.
<Do try something very small, like bloodworms. Shrimp are fine up to a point, but because they contain a lot of Thiaminase, it is sensible to use them in small amounts, no more than 25% the weekly food input. Earthworms are very nutritious, in part because they are 'gut loaded' with decaying plant matter and soil. While that sounds icky, it does mean they provide lots of useful vitamins, minerals and fibre.>
I will try not feeding for a couple days. My only worry is that he's already looking very malnourished from his rejection of food (hip bones showing, dent in forehead, etc). I will do that if he can last the couple days without food even like this.
<Well, if he's not eating, he's not eating. So whether you put food in the water or not, it hardly matters. I'd certainly stop offering food he shows no interest in. A day or two starving should make little difference, though I agree, a "skinny" Stingray is at risk.>
Water quality (ammonia/nitrite/nitrate) is still stable, nitrate at 3 PPM and I am going to change 20% of the water again today.
<The nitrate is fine; the nitrite is zero though?>
I honestly do not know about PH... maybe I made an unsafe assumption that using the same water source each time gives the same PH.
<Ah, yes, this matters. A lot of people in the US seem to have water that has been treated in various ways by the water company, presumably to improve its potability. But the chemicals used, such as flocculants, cause the pH to change dramatically within 24 hours of being drawn from the tap.
Try testing the pH of some tap water now, and then leaving the same water for 24 hours and seeing what the pH is then. You might be surprised. Also, do of course remember the basics: don't use water from a domestic water softener, do use dechlorinator, and do use a dechlorinator that treats ammonia and/or chloramine if either are issues with your local water supply. You might also want to check for copper in your tap water supply.
If your pipes are made from copper, it is possible for tap water to become contaminated. Copper is highly toxic to Stingrays, and such water supply will need to be treated with a water conditioner than neutralised copper.><<And copper ion presence would definitely send them off feed. RMF>>
`Kyle
<Cheers, Neale.>

(FW) Stingray lethargic/not swimming properly 11/5/07 I awoke this morning to my stingray in what appeared to be a death curl, turned out he was just resting his fins on the glass and a rock. but I changed 30% of the water as per my usual Sunday regimen, <We share this task, timing in common> but he is extremely lethargic and seems to be dormant after attempting to swim a short distance. He hasn't come up on the side of the glass as he sometimes used to. He seems to be swimming as though he's about to die, like a regular fish with a gas bladder problem would be swimming on its side or upside down on the bottom of the tank. I know he isn't eating as much as he should, he's been extremely thin, but I attempt to feed him at least 3 times a day. The only thing he seems to readily accept is frozen bloodworms. I've been trying live earthworms (both cooked/chopped and live whole/chopped), frozen brine shrimp, fresh cooked chopped mussels, krill, but can't seem to get any acceptance. I suspect the malady aforementioned is directly related to his feeding habits, but what can I do, or is it already too late? <This is a freshwater... Potamotrygonid... I fully suspect goiter... an iodine deficiency here, perhaps other nutritional avitaminoses... Please put the term "ray, goiter, iodine" in the search tool here: http://wetwebmedia.com/WWMAdminSubWebIndex/question_page.htm and read the cached views. Bob Fenner> Thank you, Josh

Stingray issue 7/22/07 Hi there, My question is about my fw stingray. I currently am housing 3 fw stingrays, 2 Motoros and one reticulata (teacup). Motoros are 12 in and 6 in and teacup is 6 inches . I have had them for about a year in a 265 gal with a large Pacu and 14 in silver Arowana. As of late the smaller Motoro has been swimming above where the air bubble wand and filter outtake meet. Its def out of character for her. I am using a Fluval fx5, an emperor BioWheel and Eheim canister for filtration. One of her eyes seems cloudy and closing. I lost the first ray I had a year ago and he showed some similar signs. Ammonia 0 nitrate 0 ph 6.0. Temp about 82. I feed rays jumbo night crawlers I get from bait shop and once in a while feeder goldfish but not to much. I added Pimafix. She also has a little red around her mouth. The swimming funny really has me thinking somethings up. She eats and has not lost any weight. Any helpful hints. I would really appreciate any help your site is the best. Oh and substrate is sand very easy on them. <Greetings. As you probably realize, freshwater stingrays are exceptionally difficult fish that are only suitable for very advanced, highly experienced fishkeepers. When it comes to disease, the problems are that [a] we don't really have a textbook list of stingray diseases yet and [b] many of the medications safe with bony fish are dangerous to cartilaginous fish. Now, as a general rule, when fish swim into the filter current it is usually because this is where the water quality is highest and the oxygen concentration highest. Likewise, when fish show red patches on this skin (signs of irritation) then again, water quality is something to think about. In your case, you need to be reviewing a variety of things. Ammonia and nitrite obviously (you say the former is 0, but how regularly do you test it? try testing over a week and at different times of the day, especially shortly after feeding). Nitrate needs to be as close to zero as possible, which you say is the case. But water chemistry is also important. Stingrays aren't that fussed about pH and hardness, but they are bothered by changes. So if you're manipulating your water supply to get the low pH and hardness levels you have, check to see you're being consistent. Another issue is air or water pollution: it's easy for things like paint vapours and tobacco smoke to end up in the aquarium, and these will irritate/poison the fish. Yet another issue is filter turnover. For a stingray, I'd recommend not less than 8x the volume of the tank in turnover per hour (i.e., marine quality filtration and twice that for regular small community fish like guppies and tetras). Given your aquarium is 265 gallons, that means you need filtration around 2120 gallons per hour, minimum. Your Fluval delivers about 600 gallons per hour, the Emperor 280 gallons per hour, and the Eheim I don't know how much because you don't say the model. But it needs to be *at least* 1240 gallons per hour to even make the baseline your stingrays need. Since even a really big Eheim like the Professional 3 is only producing a "mere" 450 US gallons per hour turnover, your tank is very likely (almost certainly) under-filtered. Some more general advice. Melafix and Pimafix are largely useless as treatments. While they sometimes work for some people under some conditions, they're too inconsistent to be relied on, and therefore of no value with expensive fishes like yours. Another problem is diet. Stingrays feed on a variety of animals in the wild including small fish, but never Cyprinidae. The nearest Cyprinidae are hundreds if not thousands of miles away from where they live. Why do I mention that? Because Cyprinidae -- things like goldfish and minnows -- have high quantities of Thiaminase that breaks down Vitamin B1 over time. They also contain a lot of fat. Fish that eat them in the wild, like pike, presumably are adapted to this, but most other predatory fish do not seem to be, and long term both these issues cause damage. Bob Fenner has written at length on the issue of feeder goldfish and marine predators like Lionfish. Since your stingray is, basically, a marine fish that happens to be living in freshwater because it got trapped on the wrong side of a newborn mountain range, your stingray likely will react the same way to a high fat, high Thiaminase diet as any other marine predator (i.e., poorly). On top of this, feeder fish are the Number 1 best way to introduce parasites and bacteria into your nice clean stingray aquarium. To be honest, whoever advised you to feed cheap "parasite time bombs", sorry, feeder goldfish, to something as delicate and easy to kill as a stingray deserves to spend some quality time on the Naughty Spot. The ideal foods for stingrays are either terrestrial foods (like earthworms), marine foods (like mussels and prawns), or "clean" frozen foods (like bloodworms and lancefish). All these will be safe because they have no chance of introducing parasites or bacteria into the aquarium likely to harm a freshwater stingray. Over here in the UK, live estuarine river shrimp are widely used with success and these match very closely the preferred staple diet of freshwater stingrays in the wild: large crustaceans. As you realize, stingrays have teeth adapted not for catch fish but for crushing shells. Finally, the whole sand issue in aquaria for stingrays is debated endlessly. There's some good evidence that dirty sand can trap bacteria and cause infections. This has been observed on catfish barbels for years (erroneously put down by some people to "sharp" gravel wearing the barbels down). Catfish generally shrug off such infections and re-grow their barbels when conditions improve, catfish being, fundamentally, very hardy animals usually adapted to swamps and other horrid environments. Stingrays do not have this level of robustness. So double check the sand is spotlessly clean. You should be stirring it weekly and siphoning out any detritus. Many stingray keepers prefer to keep their rays in tanks without sand to side-step this issue. Finally, do check the fish aren't able to burn themselves. It is *extremely* common for stingrays to burn themselves against the heater. The heater should be either inside the filter or covered with a plastic mesh of some kind (called "guards" and these often come with the better heaters anyway). Hope this helps! Cheers, Neale.>

Hystrix Stingray Not Eating? 1/23/07 To Whom It May Concern, <Okay> I have had a Hystrix Stingray in a 250 gallon tank for approx. 9 months and she has now stopped eating?? <Mmm, you tell me... Potamotrygonids, in fact all cartilaginous fishes do periodically seem to go on feeding strikes... generally no problem> I checked the water quality (ammonia = 0, nitrates = 0)and have even performed two water changes (approx. 20%) over the last 4 days, but to no avail? <Was I there with you?> She was eating shrimp (4-5 per day), <Mmm... I wouldn't feed this much, and not daily> bloodworm cubes, earthworms, salmon, but is no longer accepting any of the above. The water temp is approx 80-82 degrees and the PH is 6.0-6.2. I am unsure what to do, but she has not eaten in approx. 5 days and is looking very thin and weak. <Do you administer vitamins? Iodine/ide?> In the past, she was very aggressive when eating and would accept food as often as I would put it into the tank. Is there some type of medication that I should add to the water? <The aforementioned supplements> Thanks in advance for your help. Regards, Steve <Please read here: http://wetwebmedia.com/marine/fishes/index.htm The second tray... Batoids Disease, Potamotrygonids Feeding... Bob Fenner>

Motoro ray health 9/28/06 Can you help me with a problem I noticed with my motoro stingray? I've had it for 2 1/2 years, and it's size is approximately 7" round with a 6 or 7" tail. I just noticed a depression in between its eyes (on top of its head). He eats fine and swims fine and haven't noticed any changes other than this depression. There appears no injury to the outside tissue. Any idea what this may be, and is it a big concern? Any help with this is appreciated. Rob <Mmm... most likely an endocrine/nutritional deficiency centered around iodine... Do you supplement this animals foods with such? Use Vitamin inserts in its foods? Please read over WWM re Goiters of Cartilaginous fishes and Mazuri.com's site re. Bob Fenner>

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