What is going on with Blacktip reef shark?

[mr.r8rfan]

A friend of mine has two blacktip reef shark pups in a 1200 gallon aquarium and has had them now for about 3 months. They are about 18” in length, well he called me a little while ago to tell me that something had come out the anus of one of them and the shark was splashing around…he said it rose to the top of the tank and was floating on the surface while the shark was moving around. I have some experience with much smaller sharks but nothing like this so I wasn’t able to help him out. The description he gave me didn’t help too much either. He said it looked like a “taco” coming out and it was huge and the shark started splashing around all crazy then all of a sudden it sucked it back in. My best guess is it’s reproductive organ but I’m wondering if there are any other explanations and if this is normal behavior for this species in captivity.

[myerst2]

Maybe the air bladder. That's the only thing i could think of.

[mr.r8rfan]

Air bladder?? Is that something that is supposed to happen with the bladder or what? Is that a clear sign of stress?

[TheSaltwaterGuy]

Well, in some of the Benthic shark species, the female will lay "false" eggs. But because this is an active Requiem shark, I have no clue. Hopefully Ken (krj-1168) will see this thread and respond.

[mr.r8rfan]

What is a "false" egg? What would that look like? I have a small banded shark in a 300 gallon and found something in there a while back that looked like a cotton cocoon or somthing and had attached it self to a rock. When I went to see if I could remove it it appeared I pinched a hole in it and air bubbles came out. It had healed by the next morning. Then when I finally removed the entire thing the white cotton looking stuff seemed to melt of when it hit the air and the inside looked like a oyster and stunk really bad. I thought maybe this could be an egg but my banded shark is only maybe 11" long.

[TheSaltwaterGuy]

Depends on the species of shark. Nurse sharks false eggs are red in color. It probably was one. Just an attempt to get ready for mating I reckon.

[krj-1168]

Hmmm... Hard to tell.

From the description - it could be several things.

While it could be from inverting the reproductive organs - which is kind of rare. It's could also be from basically releasing waste (taking a crap). Some times requiems are known to invert the cloaca - when they defacate. Which appears to be fairly normal in requiems.

As for "False eggs" - Usually requiems don't lay eggs. Also the Blacktip reefs will need to double their present size to reach maturity. But will out grow the tank before then. Still since some species are known to simulate breeding behavior before sexual maturity. So I would say The "False egg" theory is at least a possibility.

[mr.r8rfan]

Don't black tips give live birth? But still lay eggs?? How does that work? Is this like the birds and the bees talk? lol

[TheSaltwaterGuy]

Blacktips give live birth.

[lowendmelody]

Just another example of someone keeping a species they shouldn't .......

[crazedpuffer]

Sounds like it could possibly be it's anus coming out. Normally caused by a bad diet.
What is he feeding them?

[billsreef]

<a href=showthread.php?s=&postid=11460574#post11460574 target=_blank>Originally posted</a> by mr.r8rfan
Don't black tips give live birth? But still lay eggs?? How does that work? Is this like the birds and the bees talk? lol

They hatch them out internally. Interestingly, the pups will often eat each other as they develop before it's time for birth.

[billsreef]

<a href=showthread.php?s=&postid=11460479#post11460479 target=_blank>Originally posted</a> by krj-1168
Some times requiems are known to invert the cloaca - when they defacate.

Most likely what you saw.

BTW sharks don't have swim bladders ;)

[mr.r8rfan]

Diet consist of silver sides, anchovies, and squid and the occasional damsel.
I didn't actually see what came out just gave me a description. He said it looked like a pink taco coming out and it looked like it was flat but coming out folded - apparently it did not float as I had mentioned. I misunderstood, he said it just came out and the shark was swimming hysterically then all of a sudden he sucked it back in. I also think it was part of the anus…I have a banded shark and have never seen anything like that with them before.

[jejton]

<a href=showthread.php?s=&postid=11458684#post11458684 target=_blank>Originally posted</a> by myerst2
Maybe the air bladder. That's the only thing i could think of.

Correct me if I am wrong, but sharks don't have air ( well actually gas ) bladders. Thats one of the main differences between them and bony fishes. Its why they have to swim to maintain vertical position in the water column.

[Lrgclasper]

Sharks don't have airbladders- they use liver oil and hyrdrodynamics to control position in the water column. It is likely the shark's rectum/instestine. Sometimes sharks will invert thier rectum/intestine, which results in a pink looking thing hanging out. It can get infected if another fish picks at it or the shark scrapes it. Normally it will go back to normal after some time.

[krj-1168]

Ok - the act of the shark inverting it's rectum/intestines - is called Rectal Eversion. It's a fairly natural condition which occurs in most shark species.

As for Basic Shark reproduction - there's 3 types of reproduction.

- Oviparous (external egg-layers) - these species lay eggs out in the ocean, in a leathery protective cases. This type is popular among the benthic species - such as Hemiscyllids(Bamboos & Eppies) and Heterodontids (Horns & PJs).

- Ovoviviparous (internal egg-layers) - These species lay eggs, but keep them internally until they hatch. This style of reproduction is used by the Nurse Sharks (Ginglymostomids).

- Viviparous (live birthers) - These species have a more mammalian-like style of birthing. The female cares the young(internally) in her uteri, until they are fully developed, and ready to be born. The types of sharks that practice this form are - Carcharhinids (such as the Blacktip Reef), Sphyrhnids (Hammerheads) and Triakids (Smoothhounds).

[mr.r8rfan]

Does anybody know for external egg-layers does the egg change in appearence from the time if first comes out? Or does it always look like that dark brow leathery sack?

[billsreef]

It looks just the same, sometimes a little lighter in color.

[mr.r8rfan]

Now in regards to lighting in a shark aquarium. I've read in most places that it's not very important so what is best recommended? Flourescents? VHOs? PCs? Wattage?

[TheSaltwaterGuy]

I'm running flourescents. Honestly, any lighting is fine. You could run MH if you wanted, just be sure to give the shark a place of shade to get away from it during the day.