The pics are too blurry for any type of positive ID. Try moving back from the glass and use the zoom on your camera to enlarge it (if you have zoom on your camera).

critter
 

A few years ago in my reef tank I spotted a red and black crab.It was neat looking so I left it in the tank.I had a purple and a Lavender tang dissapere.The next time I saw that little crab it was 6 inches .I caught him and never lost a fish again.A friend of mine had a large brittle star and a bunch of damsils in a tank.He was loosing a lot of fish and could/nt figure it out.One day he saw that star fish snag a fish.He said it was really fast.I always thought they were slow like slugs

crab?
 

thanks! i'll try to have a much clearer picture.

I had a green brittle star that would move 3 feet (across a 33 gallon in a second or less) and grab a damsel for breakfast, the star ate all 3 damsels in 3 mornings, after that I took it back and bought some keeper fish.

Swollen gills eh? any spots on the gills that you can see, are they pink still or discoloured? Any new rock, coral or fish added that was not QT'd? I know it seems we are not listening but we are and we'd all like to figure this out with you. Normally if the culprit is a crab, mantis etc there will be physical trauma to the body, seeing as this is not the case environmental issues/concerns or disease look suspect.

Doug

A little late getting here, and looks like everyone has already suggested ideas.

I seriously think it is a water quality issue, and not a hiker if there's no trauma. Missing fish, now that would also be concern for a hiker. But if no trauma and only bodies, water quality it has to be. ;)

Thanks for the replies, guys.

Water test kits - one is Hagen and the other which is only a month or so old is Oceans. I can advise that the numbers did not change (I do not have the numbers with me) as I tested the day I put in the new corals and also the next morning after we found the dead fish. Only readings that were different were 0.3 for nitrite and nitrate. With dead fish in the tank that is not surprising.

As to the sea apples releasing toxins, three shrimp died as well and they are inverts. Not to mention I have a firefish that is fine. Are they immune to sea apple poison?

Quick update: Found a bristle worm so going to get a trap for that this weekend. Also going to set up a bottle trap and see what it comes up with. The firefish did not show his face at all last night. This is the first day since he came out of hiding that I have not seen him. He did not even come out to eat.

I will let you guys know what I come up with, or if anything changes.

Here is the original thread to get the whole story to help solve the puzzle :mrgreen:

http://albertaaquatica.com/index.php?showtopic=13105

**edit** fixed link

I'm going to chime in on the "not a hitch-hiker" theme. Any such deaths (crabs, mantis, bristleworm, etc) should be a predatory act, and should leave signs of that.

Red, puffy gills are a sign of a number of things I've never seen in my personal experience, including parasitic infection, introduced chemical irritants (including "hot" changewater, ammonia, chlorine, etc), overdosing with additives, heavy metals (unlikely here due to the relative effects on the inverts), bacterial infections, solvents (recent home renos, painting, etc?).

If it just started happening, it is likely something you did, or your water supplier did.

Lack of Oxygen or CO2 levels too high?
 

I normally just lurk in the background around here, but I thought I would put my 2 cents in on this one. I agree with Ruth.

Clearly not enough carnage to be a killer hitchhiker. Believe me I've seen my fair share of them...

My feeling is that the bioload was just too high to maintain the oxygen level at night or the CO2 levels got too high. 6 fish in a 28 gallon is an extremely high. While you're able to maintain the water quality with weekly water changes the oxygen levels we're probably dangerously low at night as everything in the tank would be using the oxygen and nothing can be creating it (unless you have a refugium on a reverse photo period). Adding the new critters probably put you over the top. In an oxygen deprived enviroment the larger more advanced species usually go first (ie. the fish and the shrimp). Which would explain why the hermits, snails and corals survived. The firefish just got lucky and it would explain why he is now freaked out. I think I would be freaked out if I almost suffocated :wink: .

Good Luck!

Kevin

Killer pods?
 

I remember reading a post about killer pods. Not sure if that could be it but from what I read they were incredibly nasty. Anyone remember where that link is?

It talked about a diver encountering them in the ocean and having his face attacked. Apparently they show up in aquariums on occasion.

Good luck.