Engineer Gobi

Paul B · Nov 10, 2008

I once wrote that engineer gobies are kind of benign in the fact that they are reef safe and won't eat your fish. I need to re state that to they won't eat fish unless they fit into their mouth.
These eel looking fish are called "engineer gobi's" because they dig tunnels all over the place, sometimes causing the rocks to fall. They get quite large and go unnoticed because they are noctural and during the day they act like moray eels hiding most of their body with just their head sticking out of a rock.
They will eat anything and are very easy to keep.
My tank has over 25 small gobies of varying types and lately I have noticed that I am missing four of them. Two small clown gobies and a small butterfly that I collected which was a little smaller than a nickel and another fish.
The other fish was a pregnant sand sifting gobi which is a skinny fish about an inch or so long.
I was trying to take a picture of this fish and I moved a rock for the shot.
As soon as I did that, the engineer gobi darted out and grabbed the fish, head first and brought it into a tunnel.
I ran and got a large bucket and started to remove rock to find the gobi. I removed the rock on half of the tank and noticed that the engineer had a tunnel going the 6' length of the tank all the way to the bottom. It snaked under all the rocks. Eventually after about 15 minutes he let go of the pregnant fish.
The fish was too large for the engineer to swallow but 15 minutes with his head in another fishes mouth killed her.
I did a ciserian and collected the eggs but they were (of course)unfertile and will not hatch.
I am sure this engineer is the cause of the other missing fish as they were all smaller than this engineer gobi.
I had this problem before with an 18 year old cusk eel or brutlyd fish. I always wondered why I had a problem with small fish disappearing.
I will build a trap for this fish and give it away or keep it in my local water tank. If anyone wants him, let me know.
I just noticed while looking at the picture, that gobi to the right is the male partner of the pregnant fish that was killed by this engineer.

Scooterman · Nov 10, 2008

I once had two engineer Gobi's, when I got them they were about 3" long, tiny! I found out after a few years they grew really fast, they were about 8" or more & would eat & move rocks & disrupt everything, it was very hard removing them. I once spent $40 on a 2.5" Fire Shrimp, about as fast as I put it in the tank one of the Gobi's came out from nowhere & ate it whole! I think that was when I decided time to get rid of them, had to tear down the tank to get them out.
That was my experience with Engineer Gobi's!

luke33 · Nov 10, 2008

There definately cool fish and super interesting to watch but can be a major headache like you see now. Sorry to hear about that Paul!

NaH2O · Nov 10, 2008

Yikes!! Sorry to hear about this Paul!

I was excited about your pregnant goby, too

. Did you happen to take pictures of her eggs?

Paul B · Nov 10, 2008

Did you happen to take pictures of her eggs?
__________________

No I diden't but I did an autopsy and her organs liiked like they were supposed to.
She was in a community tank and got chased around by other gobies so she hid all the time. I doubt she could have laid those eggs anyway in the shape she was in which is the reason the engineer was able to catch her so easily.
He could not eat her in one piece so I am surprised it grabbed her at all but now at least I know what was happening to my other smaller gobies. They were all smaller than the pregnant one. I will buy another one of those so Ican pair them up again after I catch the engineer. It is what it is and the engineer gobi just did what they are supposed to do.
It is my fault but I will not make that mistake again. Some fish we buy very small and kind of forget about them as they grow, especially a secretive fish like this.