Missing fish in small tank

[coloradoreefer94]

I have a 20 gallon that is appox. 10 weeks old, and I stocked it with 2 small clowns, a royal gramma, a red fire fish, a Yellow watchman goby, a cleaner shrimp, 2 scarlet hermits, a porcelain crab, 2 trochus snails, a nassarius snail, and a tiger conch.

Within the past 4 weeks, my YWG and fire fish have both disappeared out of nowhere. The goby about 3 weeks ago, and the fire fish 2 days ago. They both seemed fine before they went missing and were swimming around and eating. I test the water biweekly and today as well, and the parameters are all in a healthy range, and 0 ammonia and nitrite. The clownfish are alive and well, and I also have about 15 coral frags that are all healthy and growing. The only noticeable issue with the tank is a moderate green algae outbreak that I have been working on fixing.

Is it possible that these fish died randomly and the clean up crew consumed them overnight before I could see that they have died? It is strange to me that they just disappeared so quickly. I have a glass lid that covers most of the top except for about an inch to allow for gas exchange. I did not see any fish on the floor outside the tank, but I do have a cat so I don't want to rule out the possibility that they jumped out and got eaten. Thoughts??

 

[Mr. Mojo Rising]

Do you have a lot of rockwork? Gobies are shy and like to hide in the rocks and might not come out for some time until they feel comfortable.

What about the RG you don't mention what happened, only that the 2 clowns are still alive. RG is missing too?

What type of test kit are you using?

Is the water well oxygenated?

I'll also add that its a lot of fish for that size tank and they were added too quickly IMO. Its important to go slowly in this hobby.

 

[IceNein]

If it's an AIO, it's possible that something has made it into the back chambers. I was sitting at my computer and I heard a plop, looked all around for a fish flopping around and my tailspot had jumped from the display to the back. He had to hang out there for a week until I could drain the back and pull him out by hand.

The little dude was small enough that he could swim through the baffles between the return chamber and the central chamber.

 

[ScottJ]

Murderous clowns perhaps?

 

[TX_REEF]

check the floor and under the stand? Gobies especially are jumpers.

 

[coloradoreefer94]

Do you have a lot of rockwork? Gobies are shy and like to hide in the rocks and might not come out for some time until they feel comfortable.

What about the RG you don't mention what happened, only that the 2 clowns are still alive. RG is missing too?

What type of test kit are you using?

Is the water well oxygenated?

I'll also add that its a lot of fish for that size tank and they were added too quickly IMO. Its important to go slowly in this hobby.

10 lbs of rock, the goby and the firefish would be visible everyday at some point or another until they went missing, then all the sudden no sign of them. RG still doing great as well. Using salifert test kits, lots of water movement at the surface as well as a powerhead on the side wall. And yes, probably added them a little too quickly I will admit, though they seemed to be fine for multiple weeks after getting them before they disappeared. I will mention I added all the fish at least a week apart not all at once.

 

[coloradoreefer94]

If it's an AIO, it's possible that something has made it into the back chambers. I was sitting at my computer and I heard a plop, looked all around for a fish flopping around and my tailspot had jumped from the display to the back. He had to hang out there for a week until I could drain the back and pull him out by hand.

The little dude was small enough that he could swim through the baffles between the return chamber and the central chamber.

Not in the AIO chamber or on the floor. If they did jump out, I will assume my cat ate them:(

 

[Tahoe61]

Twenty gallons at 10 weeks x 5 fish = New Tank Syndrome.

It's a hobby of patience. Consider quarantine for new introductions. It can be extremely frustrating but slow wins the race.

 

[TankYouVeryMuch]

Are you using live rock? Is it possible you’ve introduced a Bobbit worm or some other kind of predatorial pest?

I’d try using a red light (if you have one) and taking a look in the aquarium after lights out and see if you spot anything unusual moving around. The fact that the fish disappeared entirely is what makes me wonder if something is dragging them back to a lair or hidey hole.