Tank troubles, iatrogenic    3/14/12
Hello, I was given a tank a couple of years ago with a group of fish including 1 now 10inch id shark
<Grows to a few feet... why don't you, others search, as directed, on WWM ahead of writing us?>
(he was alot
<No such word>
 smaller when i got the tank) 4 Tetras and a large Pleco 8 inches . I wasn't told anything about fish keeping just keep the temperature right do water changes watch out for signs of infection (knowing what i do now i wish i did my research earlier).
<Honest>
My tank is 4ft by 2ft by 1ft. Since i upgraded to this tank. A few problems have occurred.  Iv never had disease in the tank. In all the time i had it, However i decided to buy some new tetras and then the problems seem to start (fin rot).
<Environmental...>
Also my Pleco fights with my Id shark  and in diving around the tank damaged the end of his two front fins very slightly. It appeared to be heeling very well so i didn't put any treatments in the tank as i was already treating for the fin rot and i didn't want to add more chemicals after reading the id shark having no scales is very sensitive to treatments
<Ahh!>
 and i don't own a hospital tank. The end of the fin healed over but after some days turned red on the end of both fins. Also he seems to be covered in tiny air bubbles. I'm not sure if this is normal.
<Not; again, env.>
Apart from this he eats like a horse, Holds his fins out and dances for me still and is showing no other signs of disease. After seeing the red develop on his 2 fin tips i treated the tank with anti bacterial for ulcers and infections and so on (what the pet store advised). I cant get rid of the red in his 2 fin tips,Im presuming it is an infection.
<READ here: http://www.wetwebmedia.com/FWSubWebIndex/PangCatDisF.htm
and all the linked files above; compatibility>
After treating him twice no change i feel stuck not knowing what to do help please!
<... help yourself>
Also i added two albino red fin sharks to the tank last week  just over an inch long
<Likely will be inhaled, killed by the Pangasiid>
(since i have the tetras who are small i didn't see a problem with the bigger fish eating them he leaves everyone alone mostly) All was great they seem to hide alot but i read that was normal. Last night before i went to bed they were both swimming around happily playing, In the morning i woke up and found one of the small albino sharks dead. The only sign of possible death i can see is bleeding under the skin where i think the heart is only no where else. His colours are still bright a beautiful like before. I'm worried something is going on in the tank now. I love my 2 large fish alot i don't want anything to happen with them. Also i never knew much about water testing and when i read online or go to the pet store im abit overwhelmed with so many different things with expensive prices! i don't have alot of money, Please can you advise me of the main and most important tests i need to carry out to determine what is going on in my tank and tips how to treat my Pleco and save my tank before all hell breaks lose and everyone dies. Thank you for your time
<Learn to/use the search tool, indices on WWM, and run your writing through a spell- and grammar checker before sending to us if writing again. Bob Fenner>
Re: Tank troubles. Why we eat the rude    3/14/12
Thank you for your rude reply, Firstly I know exactly how big the catfish grows that's why I didn't search this.. I didn't even ask you for the size so not sure why you needed to be rude there. I was nervous about posting anywhere else in fear of a rude response and I find it hard to use your site and read through things to find what I need unless sent there by Google!. So I thought it would be better to describe my tank and get the right advice and ask you my self! Thanks for the English lesson, I wont be writing your site again for advice :) not sure why you linked me to the Pangasiid page i have already been there a million times. It is the Pleco who is sick not the id shark as I said in my previous email to you. Have a nice day!
<And you>

Stress or not happy with food? Pangasiid incomp., FW stkg. period/hex tanks   1/24/10
I just revamped my tropical tank.
<Oh?>
New (plastic) plants, new decorations and reintroduced all the fish at the same time in an effort to reduce stress. I have provided as many hiding places as possible for my fish.
<Sounds promising.>
It's a 55-gallon hex tank,
<Do be aware these are generally not good choices, and in terms of stocking a hexagonal aquarium of 55 gallons will only hold the same number of fish as, say, a 30 gallon rectangular one. Why? Because of surface are to volume ratio. A hexagonal tank this size has the same volume but lower surface area than a 55 gallon rectangular one. Less oxygen can dissolve into the water, and less CO2 can diffuse out. I don't recommend hexagonal, spherical or any other shaped aquarium other than a low, long rectangle. Sometimes, old school is the best!>
I keep the water at 78 degrees and have a Penguin filter that I keep two cartridges in at all times. (Done to increase the amount of carbon to help keep the water clear.)
<Actually, carbon only removes dissolved organic chemicals, the stuff that makes water tinted yellow over time. It has zero benefit in terms of removing solid particles such as silt that make water cloudy. Indeed, it's rather better to take out the carbon and replace with filter floss if silty water is a problem. In most freshwater tanks, carbon is redundant.
Manufacturers sell the stuff happily, given how massively overpriced it is, but me, I prefer to save my pennies.>
The water is still a little cloudy from the water change I did yesterday, but it's clearing up as expected.
<Indeed.>
In the tank we have a Plecostomus (about four to five inches in length - the giant one we traded in because I didn't need both of them in the tank),
<Has no place in a tank this size/shape.>
two small Cory catfish and an incandescent shark.
<Corydoras should be in groups of 5+ specimens of each species, and an Iridescent Shark (Pangasius hypophthalmus) has absolutely no place in this aquarium. Given its maximum length is well over 120 cm (more than 4 feet)
I'd strongly argue this fish shouldn't even be in the fish trade. Sure, most specimens in aquaria don't get that big. That's because they usually end up dead first. But the lucky survivors still get to a good 60 cm (2 feet) or more in length, and public aquaria really are fed up with taking unwanted specimens. On top of that, this is a schooling, riverine species that needs to be kept in groups in a spacious aquarium. In small tanks -- and yours is TINY by the standards of the species -- this fish ends up throwing itself against the glass, damaging its eyes. Many, MANY specimens are blind precisely because of this (and needless to say, with a beaten up head and cloudy eyes, pretty ugly looking as well).>
Obviously those are our cleaner fish.
<NO such beast. If you imagine any fish, ANY FISH, will make an aquarium cleaner, it's time to do some reading. Think about it. Adding fish adds the amount of food you need to add. That fish defecates, meaning there's more silt. That fish excretes ammonia, so there's more work for the biological filter. That ammonia becomes nitrite and then nitrate, feeding algae. So the tank becomes more algae-ridden. In every possible way, adding fish makes tanks dirtier. End of story.>
The rest of the tank holds two Mickey Mouse platys, two sunset platys, one female Betta, one Dalmatian molly and five tetras.
<Finally, some fish that make sense. I'd argue the Molly is better in a community where adding marine salt mix is an option, but I'll let that pass for now. These are small fish that would be happy in a tank your size and shape.>
So far it seems like everyone gets along,
<So far...>
though I admit my female Betta is a little ticked off since she used to rule the roost (it used to just be her, the Corys and the Pleco). But she's doing pretty well, she just sort of chases the others around checking them out, but I haven't noticed any aggressive behavior on her part.
<Fine.>
I noticed today when I fed them, that the platys would take the food in their mouths and then immediately spit it back out. It's tropical flakes, it's what the people at the pet store said to feed them. (Which, from what I've seen on your site isn't the right thing to be feeding them.)
<Indeed. While flakes are fine up to a point, these are herbivores, and their diet should include as a staple Spirulina flake, plus things liked cooked peas and Sushi Nori. It won't kill them giving them flake, but offer them the green foods too. Usually, tetras ignore Spirulina flake, but catfish happily eat it. Indeed, Corydoras eat a lot of algae in the wild.>
Are they spitting it out because they don't like the food, or is it because they are still stressed after the water change I did yesterday?
<Unlikely because they're "unhappy" about the water change, but check water quality. If you have added a bunch of fish all at once, or were too aggressive when it came to cleaning the biological media in a mature filter, you could have higher than zero ammonia and nitrite levels. This would explain their odd behaviour. Also check the flake isn't stale. Open pots last about 6-8 weeks in a dry climate before they lose their savour.
Don't buy huge pots expecting them to last all year. If you must, decant small portions from a big tub into a small pot, and store the big tub in an airtight container somewhere cool and dry (just like you'd do with any dried human food, like cereal). Next up, offer a variety. Fish get as fed up with the same thing every day as you would. Once a week offer live brine shrimps or wet-frozen bloodworms. Finely chopped (raw) fish fillet or seafood is good too. Don't add anything from warm blooded animals though:
no meat, no chicken, and no dairy. While fish will often eat these things, with a very few exceptions, in the long term such foods cause problems.
Shredded beef heart and hard boiled egg yolk are the two main exceptions. On the other hand, all sorts of plants foods can be tried, including softened vegetables like courgette, spinach, lettuce and cucumber.>
Should I worry - or are they actually getting some of the food despite some of it coming back out?
<If it is still occurring within a couple days, yes, be concerned.
Certainly check water quality now. Platies need hard, basic water (10+ degrees dH, pH 7.5-8) with 0 ammonia and 0 nitrite. They actually prefer slightly cool water, around 22-25 C. Do review the needs of fish prior to purchase, and choose species with similar requirements.>
They all swim all over the tank (except for the molly, she hangs out near the top, and she's pregnant, so I'm not surprised by this behavior)
<Could be unhappy; review "the Shimmies" and be aware of the VERY specific needs Mollies have for long term health.
http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
Most folks keep 'em wrong, and so end up with sick Mollies.>
- so I think they are all healthy. I'd just like to head off any potential problems to keep them from getting sick in the future. I'm an amateur, so I don't know everything, but I'm trying to do what's best for the fish ... I hate to see animals suffer, be they marine or not!
<Quite right! I applaud your philosophy here.>
Thanks for the help!
Trysh
<Happy to be of help. Good luck, Neale.>
Re: Stress or not happy with food?
Neale, thanks for the advice.
<Pleasure.>
Wow, I thought I was doing better ... but I guess I still have a lot to learn!!
<As do we all.>
I would prefer a rectangular tank, but I inherited the 55-gallon hex and you know, when we're talking a free setup, you take what you can get.
<Indeed. But it's also true that if you do inherit a tank like this, you understand the limitations, and choose fish accordingly.>
I would like to clarify one thing - the shark is an incandescent shark catfish. It's not the iridescent shark you referred to. :)
<Exactly the same fish. Pangasius hypophthalmus. Google the Latin name, and take a look. Indeed, Wikipedia has a photo of this fish alongside the common name you used.
http://commons.wikimedia.org/wiki/File:Iridescent_Shark_Catfish.jpg
I'm not a big fan of common names for precisely this problem. With a Latin name, you know where you stand. With common names, who knows what kind of fish is being sold!>
I'm not that inhumane!
<Most folks aren't inhumane deliberately... but the nature of the fishkeeping hobby is that the variety of species on sale far exceeds the abilities of most aquarists to keep them properly.>
But, as you so aptly pointed out, the catfish and Pleco aren't necessary...
<Quite.>
Even so, thanks for the help. I'll cook up some peas with dinner and offer those to my patties and see if that helps.
<Hope this works. Cheers, Neale.>
Re: Stress or not happy with food?
Stupid petstore guy! ARGH :) I'm sure you hear that a lot.
<Unfortunately, yes. What can I say? I try my best, but there's just one of me, and fifteen million bozos out there. Cheers, Neale.>

Can I put a Iridescent Shark and a Jack Dempsey together? <<BobF's go>> 3/28/09
For a while... I was searching the web and found your site and it seemed like you guys knew what you were talking about. So I wanted to ask you a question. I have a 75 gallon tank right now and I have a 4 inch Jack Dempsey and a 6 inch Iridescent Shark, and I was wondering if my Jack Dempsey would pick on my Iridescent Shark or if they would be fine. (I am aware that that Iridescent Sharks get quite big and once it grows too big for the tank I will get a larger one. I know that my Jack will get bigger too.)
<Mmm, in this sized volume, starting these two at the sizes you mention, I do think you won't have troubles for a while... the Jack Dempsey will likely leave the catfish alone... and depending on your foods, feeding, the "shark" may not grow so large as to ingest the cichlid for a year or more. Bob Fenner>

Can I put a Iridescent Shark and a Jack Dempsey together? <<Now Neale>> 3/28/09
I was searching the web and found your site and it seemed like you guys knew what you were talking about.
<Modesty forbids...>
So I wanted to ask you a question. I have a 75 gallon tank right now and I have a 4 inch Jack Dempsey and a 6 inch Iridescent Shark, and I was wondering if my Jack Dempsey would pick on my Iridescent Shark or if they would be fine.
<Wouldn't be my idea of a marriage made in heaven. JDs are territorial, and while they generally ignore open water schooling fish too big to eat, such as barbs, anything more threatening is likely to be eyed with suspicion.  Iridescent Shark by contrast are *schooling* fish and singletons are extremely nervous. As this fish matures it's going to feel steadily more skittish, and it's a sad fact most Iridescent Sharks bash their heads in at some point. You hardly ever see any specimens reared by home aquarists that have unmarked heads or eyes.>
(I am aware that that Iridescent Sharks get quite big and once it grows too big for the tank I will get a larger one. I know that my Jack will get bigger too.)
<Wild JDs will get to about 20 cm, though that's uncommon anymore given the amount of inbreeding. So unless you have a wild fish, 15, 18 cm seems to be typical. Iridescent Sharks by contrast do get massive. Even in aquaria they routinely top 60 cm, and 90 cm specimens are not uncommon. Wild fish supposedly get to well over a metre. Cheers, Neale.>

Bottom feeder suggestions for tanks (Oh no, Pangasianodon; run, run!) 2/11/09 Hello WWM crew, <Hi,> In my 30 gallon hexagon, I have 2 Kribensis cichlids. I'd like to add maybe 2-3 fish that are middle to top level dwellers. <With Kribs? Most anything that stays at the top should work. Danios are the obvious option, but lack of swimming space may limit things. The problem here is that hexagon tanks are notoriously poor in terms of fish stocking capacity. They have a terrible surface area to volume ratio, meaning little oxygen diffuses in compared to the standard broad but shallow rectangle. You've also got less swimming space, so while Danios would be great in a 30 gal. rectangle, they're less happy in a deep but narrow hexagon. All things considered, I'd consider the smaller Danios like Zebras and Pearls, or alternatively White Cloud Mountain Minnows, in both cases assuming the temperature is no higher than 25 C (77 F), since neither likes super-hot water. (Nor do the Kribs, by the way.) Alternatively, you could go for surface swimmers that don't move about much, for example Silver Hatchets or even a single African Butterflyfish.> Can you recommend a bottom dweller that's tough enough to handle the cichlids but efficient in eating uneaten food? No matter how careful I am with trying not to overfeed, my cichlids are not interested in eating much. <Then feed less! Even if you add fish, that uneaten food gets turned into ammonia, and then into nitrite, and ultimately nitrate. Ammonia and nitrite are immediate killers, but your filter should remove them just fine. Nitrate is an insidious killer, and if you skip water changes for a couple of weeks, nitrate levels can easily get high enough to kill cichlids. Seriously, cichlids (including "hardy" Kribs) are sensitive to levels above 20 mg/l, so handling uneaten food isn't the goal, keeping excess food out is. Personally, I'd avoid catfish with Kribs: Kribs are pretty vicious when defending their territories, and can damage things like Corydoras (biting out there eyes!). Again, you have the problem of a poor surface to volume ratio, meaning that there's less "bottom" in this tank than would be the case with a 30 gal. rectangular tank. As should be apparent, while hexagonal tanks might look nifty, they're actually pretty seriously compromised in terms of keeping fish. My best suggestion would be to go with some of the snails, like Nerites or Tylomelania, that don't breed much/at all in aquaria, or even shrimps like Cherry Shrimps. These will all be ignored by the Kribs, and will help eat algae, uneaten food, etc., up to a point at least.> My 30 long tank has 20 assorted platys, swordtails and mollies. I'd like to add a few Corydoras in this tank but I'm already overcrowded. I use a Penguin 350 filter and no salt in this tank so would this be okay? <I'd not add Corydoras to this system. I like the fact you've given these fish space, and by choosing livebearers, you reserve the option to add marine salt mix at, say, 3 grammes per litre, if the Mollies start getting sick (as they often do in busy freshwater tanks). If you really must add something, consider making the water slightly brackish and getting something like Knight Gobies. Not only are these attractive fish, they're very efficient predators that will keep the numbers of livebearer fry down!> I have 4 iridescent sharks, 2 parrot cichlids, 3 black skirt tetras, 1 kisser and 1 Danio in my 55 gallon tank. Can I add a small Pleco, which one? <You are MASSIVELY overstocked already. Do you have any idea how big those Iridescent Shark Catfish will get? Do take a look at the Fishbase page for Pangasianodon hypophthalmus, here: http://www.fishbase.org/Summary/SpeciesSummary.php?id=14154 http://www.fishbase.org/Photos/ThumbnailsSummary.php?ID=14154 See the fishes these chaps are holding in the photos? That's your catfish. While 130 cm (4 foot) specimens are not common in aquaria (!) they can and will reach about half that size, and astonishingly quickly. I simply cannot stress this strongly enough: these aren't fish for the home aquarium, and the majority of specimens end up having to be killed or given away to zoos (who don't really want them). For what it's worth, most any common Plec species, e.g., Pterygoplichthys multiradiatus, would be fine in a 55 gallon tank, assuming strong filtration and regular water changes. Do understand that the common Plecs of the hobby, Pterygoplichthys spp., get to at least 45 cm (18 inches) within 3-4 years, and are incredibly messy vegetarians. They need filters rated at not less than 6 times the volume of the tank per hour (i.e., at least 330 gallons per hour in your case) and big (50%) water changes every week or so. Otherwise your aquarium will end up looking extremely murky.> Thank in advance for your help. Audra <Happy to help. Neale.>

Re: Bottom feeder suggestions for tanks (Oh no, Pangasianodon; run, run!) 2/11/09 Hi Neale, <Audra,> I agree with you about the 30 hexagon, I only bought it because it looked good. It took me a long time to decide what to put in it and my Kribs are already spawning after being in the tank for a week. I'll consider the Zebra Danios. <Cool.> In the 30 long, my mollies have done well without salt, so I won't be venturing into brackish water for them at this time. <Fine. But I'd still recommend keeping them with tankmates that at least allow you the option of using a therapeutic dose of marine salt mix, even if you don't actually go fully brackish. Hence, salt-tolerant livebearers and killifish good, soft water catfish and tetras bad.> Thanks for the pictures on the sharks. I nearly had a coronary (kidding). But I've known about their size for a while now. Two of my iridescent sharks are about 10 yrs old now and 7 in. long, the other two about 5 yrs old and 4 in. long. <Hmm... still quite small. May well be one of the other Pangasiid species. None make great aquarium fish, though, even "tiddlers" like yours. Nervous, skittish animals prone to damaging their eyes, in my experience.> If I had done my research years ago, I would never have bought them, but they are my favorites. <They are certainly nice fish. Just difficult to house. Yours have done extremely well to have lived such a long time. By NO means the usual thing.> I plan to move the tetras, kisser and Danio out once the cichlids get bigger, so my sharks will have more room. My dream tank is a 110 gallon for them but this will have to wait. <Indeed.> I do 3-20% water changes a week on each tank so this helps keep things in order. I love Corys but I don't have an existing set-up where they could fit in. <Tell me about. My poor Peppered Catfish get attacked or nipped or chased wherever I seem to put them.> Thanks for all the suggestions Neale. Audra <Cheers, Neale.>

Re: Tank mates prob. (Oh no, not Pangasius hypophthalmus!)  12/25/08 Hello dear Neale, I hope you will be fine there. Neale I want your help that I have 2 iridescent sharks and 2 giant Gouramis in 90 gallon right now. <Hello Ali. I'd be a lot more "fine" if my time wasn't being wasted. I don't mind offering advice, but when it's ignored, and you come back for more advice, that isn't really very good for my ego! Let me be 100% crystal clear on this. You have NO BUSINESS at all keeping Iridescent Shark catfish (Pangasius hypophthalmus). Firstly, they are SCHOOLING fish. Two specimens is not a school; you need groups of 5 or more. Next, they get to 130 cm (over 4 feet) long and can weigh over 40 kilos (100 lb.). There is NO WAY you have the space to keep such large fish. Most specimens damage themselves in aquaria because they cannot handle things like glass walls. They become blind for example, because they bump their eyes into things. Giant Gouramis (Osphronemus spp.) are not much smaller, typically around 60 cm in length and a weight of 9 kg (about 20 lb.). Individuals can be very territorial towards others of their species, and I suspect the two specimens you have will not get along once mature.> But Neale I am very interested to keep 2 black ghost knife and 2 parrot fish with them. <Get rid of the Pangasius hypophthalmus first. Then worry about maintaining good water quality for six months. Understand Apteronotus albifrons will die at the first sniff of ammonia and nitrite, and will not tolerate pH changes. So keep testing water quality and chemistry in your tank, and if it is ABSOLUTELY perfect every single week from here to June, then maybe think about a Knifefish. Otherwise, leave them alone!> Can they live happy and calm with each other in one 90gallon tank? <No.> Thank you, Ali <Ali, please understand the best I can do is to prevent you making mistakes. In this case, I've said repeatedly that Pangasius hypophthalmus is NOT a fish you (or ANYONE ELSE) should keep as a pet. It is a food fish, not an aquarium fish! Merry Christmas, Neale.>

Re: Tank mates prob. (Oh no, not Pangasius hypophthalmus!)  12/25/08 Hello dear Neale, I am sorry I didn't mean to hurt you; I always listen to your advice and did whatever you said. <Ah, that's the best Christmas present!> I have returned the iridescent shark and giant Gourami back to the pet store. <Extremely WISE decision.> Now I am doing what you have said about maintaining the water condition. Please suggest me any fish that you think is best, ill introduce them when water condition become normal. My goldfish are fine now they are doing well. <I would start with a group of either Bronze or Peppered Corydoras (Corydoras aeneus or Corydoras paleatus). Get six or more specimens of each species. By all means keep both! These catfish work EXTREMELY well with Goldfish, and enjoy the same water temperature. Corydoras will do just fine at the 22-25 C that Goldfish enjoy. They stay relatively small, are completely peaceful, and being air-breathers, will not suffer in summer if the water gets too hot. Another great fish to keep with Goldfish is the Weather Loach (Misgurnis anguillicaudatus). It gets to about 20 cm, is great fun, and works well in groups of 3-4 specimens. Giant Danios (Devario aequipinnatus) are fun with Goldfish, but they are boisterous and may terrorise fancy Goldfish; they work best with standard (non-fantail) varieties such as Common Goldfish, Comets and Shubunkins. Perhaps surprisingly, the Variatus Platy (Xiphophorus variatus) can work well with Goldfish; it's a herbivore, so will do well on similar foods. Couple other choices include White Cloud Mountain minnows (Tanichthys albonubes) and the Green Barb (Barbus semifasciolatus).> Thank you, Merry Christmas, Ali <Likewise, and a happy new year to you, too! Cheers, Neale.>

Holes in a Paroon shark. African Cichlid, Pangasiid incomp.  12/30/06 Hello! I have a Paroon shark <Pangasius sanitwongsei Smith, 1931... a REALLY big catfish> that has been in a tank with cichlids for about 5 months now. I had a Moray Eel <...> for about 3 days and after researching it (should have done that before I bought it) <Yes> I decided to give to my cousin's saltwater fish store. In the morning the day I gave him up, he was belly up in the tank, then when I came home, his head was by my sharks spot in the tank and it was obvious that they were bitten. I put medicine in the tank and tried to nurse them to health. It was apparent one shark would loose <lose> his eye because it was bloody then just turned black like his skin. It was almost like his skin grew over the eye.  Well my cichlids picked on the sharks and would bite his eye and his side fin (in front) <Incompatible...> so I put the shark into my 10 gal feeder fish <... dismal> tank with some medicine so he could heal in peace. He has been in the tank for 3 weeks and where his eye was started to turn pink. Silly me I thought it might be regenerating. Well, now there are holes where his eye and fin used to be. It appears like its rotting or something. I have no clue what is going on. Can you help and let me know what it is and how I can treat him? Thanks! Jennifer Mercer <What re water quality, testing... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwdis3setsfactors.htm and the linked files above. Bob Fenner>

FW Minnow Sharks, Pangasiid Catfish Shark... comp. mostly  6/5/06 Crew: <<Paula. Tom with you.>> I was reading your information on the different types of sharks/minnows. Under the Apollo shark it said "best kept singly." Does this mean only this fish in a small tank or only one of this type of fish along with others in a tank? <<These fish don't get along with others of their species or with similar types of fish. Not an uncommon situation with certain varieties.>> Also, will tri-color, iridescent, and Apollo sharks get along without fighting in one tank that holds about 40-50 gallons? <<The Tri-color (Bala) Shark will quickly outgrow this tank. It's active and fast requiring lots of swimming room. Scratch the Iridescent Shark from your list completely. It can reach over three feet in length and shouldn't be sold to hobbyists. The Apollo Shark will probably see the Tri-color Shark as an adversary due to the similarities in their appearances. A 50-gallon tank would probably suffice for the Apollo Shark, however.>> Thanks for the help. Paula <<Please continue your research, Paula. I commend you for doing your homework but there's still much to learn. My best. Tom>>