Disappearing new fish, bullet goby guilty?

[Benoit Martin]

So let me start by explaining my situation and then I'll have several questions.

A little over 2 weeks ago I introduced a bullet goby (wrongly sold as a dragon goby BTW) and a royal gramma to my 120G tank which had 2 young clowns and a cleaner shrimp.
As soon as the royal gramma was in the tank, he found a little hole in a rock and stayed there for the rest of the day. The next morning the gramma was nowhere to be seen and I haven't seen it since.

Yesterday I introduced a purple firefish which quickly went into a hole in the sand under one of my big rocks. I could see its head while flashing a light in there yesterday but now I can't find it anymore. Tonight, I could see the goby go in and out of that hole.

The hole goes all the way underneath the big rock. Since I put the rocks first and then the sand, I suspect that there is a big cave underneath that rock.

Finally, the tank finished cycling a couple of months ago and I test water regularly and besides a little bit more nitrate than I'd like (~3ppm) all other parameters are good and stable. I do my 10% water change every other week.

The reason why I suspect the goby is that it's the biggest of the fishes (not by a lot), it always hangs out close to that hole and I have seen it chase away fish trying to go in its area. Not really aggressive but of all the fishes it's the only one to be somewhat territorial.

- is it possible that the goby corners those scared fishes in the hole and kills them?
- how long can a fish hide this way if it doesn't come out for feedings?
- should I move my rocks to see what's going on under there? I'm worried that'll cause too much disturbance.
- should I try to push sand in the hole to close it once all fishes are accounted for (or considered dead)?

Sorry for the long post and many questions. I really appreciate the help.

Losing those fishes as soon as I introduce them to the tank is starting to distress my 10yo son (and me a little too) [emoji39]

 

[James M]

A goby doesn’t scare fish into its hole and kills them.
Fish can hide for a long time. Gobies can hide for weeks and still be alive and well.
Don’t move your rock as you will collapse the gobies cave and possibly kill it. Don’t try pushing the sand.
If any dish are dead you cuc will dispose of them quickly

 

[Benoit Martin]

Hi James,

thank you for the response. I didn't mean to imply that the goby was voluntarily getting the other fish in its hole. It just happens that he likes to swim in and out of a hole under my rock where I believe my new scared fishes like to hide. I am just worried about what may be happening in that hole when multiple fishes are there.

I have been reading more about hiding fishes and I am glad to see that fish can go hiding for a long time but I am still concerned that the royal gramma and firefish being pretty small, I am not sure how long they can go without eating. I am also not sure how much uneaten food may make its way to the hole.

I will be patient and won't disturb any of my scape... I'll just continue to hope that they'll pop up some day.

Should I be adding some copepods to provide food for them in case they are still alive?

 

[Frtdrmrose7]

Did you QT any of these fish? If one brought velvet into your tank it can kill rather quickly. The goby and clowns may be resistant to it due to their slime coats. I’m not saying it’s velvet or that’s the cause just giving you something else to consider.

 

[Benoit Martin]

Did you QT any of these fish? If one brought velvet into your tank it can kill rather quickly. The goby and clowns may be resistant to it due to their slime coats. I’m not saying it’s velvet or that’s the cause just giving you something else to consider.

I did QT and clowns, goby and azure damsel look healthy. Would the damsel be affected by velvet?

What would it look like?

 

[Frtdrmrose7]

I did QT and clowns, goby and azure damsel look healthy. Would the damsel be affected by velvet?

What would it look like?

Velvet could present with a golden sheen or powdered appearance. Can also look like ich but too many spots to count

 

[Angel_Anthias lover]

Is the bullet goby a scissortail dartfish, if so i highly doubt they would do any harm to ankther fish, however firefish are very similar in shape and relatively closely related to them so it may see it as a threat however i doubt this

 

[Benoit Martin]

The goby is a sleeper banded bullet goby.
The pictures below are not mine but those are the same as the goby, gramma and firefish involved in my drama

 

[Angel_Anthias lover]

Ah i see now sorry, has the drama resolved at all?

 

[Halal Hotdog]

I cannot see the sleeper bullet goby killing any fish. I have a sleeper golden head goby and he is one of the most skittish fish I have ever kept. What I am reading about the bullet goby online make it seem very similar to my goby.

 

[Benoit Martin]

Ah i see now sorry, has the drama resolved at all?

No worries. And no, those 2 fishes are still MIA.
It probably bothers me more than it should but it's my first tank and I'm disappointed and frustrated at not knowing what I may be doing wrong

 

[Benoit Martin]

I cannot see the sleeper bullet goby killing any fish. I have a sleeper golden head goby and he is one of the most skittish fish I have ever kept. What I am reading about the bullet goby online make it seem very similar to my goby.

It seems pretty unanimous in this thread that the goby is likely not the culprit.

Mystery will persist but I am very tempted to carefully remove the big rock this weekend to find out if the fish is even underneath

 

[mta_morrow]

I have had purple fire fish and royal gramma in all my tanks.

They can hide a long time.

My current tank the fire fish cruises the whole tank.

The gramma just started coming out of his hole a couple weeks ago after almost a year. He is now visible and active on the right side only.

In my first tank, the royal gramma was all over and the firefish hid for about 6 months.

They are both hardy fish. I would give them time to feel safe.

As stated above, don’t move the rock as you may injure them.

Also keeping your hands out of the tank will help too (I know, this is a tough one!)

 

[Angel_Anthias lover]

Is there any chance the fish are coming out of the rocks at the back where you cant see them?