Lawnmower Blenny aggressive towards Yellow Watchman Goby

[durt.kobain]

Hi everyone, yesterday I added a yellow watchman goby to my tank that has been up for 3 months now. I have a lawnmower blenny that has been in the tank since the first fish were added and is very sociable and gets along very well with the other fish, but I just noticed he has been very aggressive towards the new goby I added. He has never done this with any other fish I have added any advice on what I can do? Thanks in advance!

 

[tsouth]

You can monitor, but I would suggest removing one or the other. They are too similar in shape and the blenny will continue being aggressive unless you intervene a-la removal or partition.

 

[Fishbird]

How big is your tank? Which fish do you have? My first guess is that the blenny is threatened by the goby because they occupy the same types of habitat and your tank is small enough that the blenny considers it all its territory.

 

[durt.kobain]

You can monitor, but I would suggest removing one or the other. They are too similar in shape and the blenny will continue being aggressive unless you intervene a-la removal or partition.

Thanks for the advice I am new and still learning every day! I will remove the goby if the Blenny is still aggressive to the point where he hurts him.

 

[durt.kobain]

How big is your tank? Which fish do you have? My first guess is that the blenny is threatened by the goby because they occupy the same types of habitat and your tank is small enough that the blenny considers it all its territory.

I have a 32 gallon biocube 2 clowns, the lawnmower blenny, then just added the yellow watchman. That makes sense I will remove the goby if the blenny starts to hurt him. Still new and learning every day thanks for the help!

 

[Sebastiancrab]

I have a 32 gallon biocube 2 clowns, the lawnmower blenny, then just added the yellow watchman. That makes sense I will remove the goby if the blenny starts to hurt him. Still new and learning every day thanks for the help!

Just know you may find yourself with a dead or very injured fish! I would go ahead and remove him.

 

[durt.kobain]

Just know you may find yourself with a dead or very injured fish! I would go ahead and remove him.

Thank you I will! Last thing I want is an injured fish due to me.

 

[Adam Schindler]

They clash just based on similarities in appearances and behavior as well. Also like someone else pointed out they prefer the same areas for the most part. So you’ll see territorial clashes if the environment is small enough. I had the same thing going on with a watchmen Goby and a lawnmower Blenny in a 90g. Plenty of rock and space for each to hide and they still duked it out plenty.

 

[durt.kobain]

They clash just based on similarities in appearances and behavior as well. Also like someone else pointed out they prefer the same areas for the most part. So you’ll see territorial clashes if the environment is small enough. I had the same thing going on with a watchmen Goby and a lawnmower Blenny in a 90g. Plenty of rock and space for each to hide and they still duked it out plenty.

Thanks for the help my man, didn’t even think about that when I put the goby in. The blenny loves to swim around the whole tank and gets along with my clowns very well so I understand why there would be a territory issue. Still learning so thanks for the help!

 

[Crashjack]

I've had both a LMB and currently have a Starry Blenny with a YWG in my DT, and they completely ignore each other and don't occupy the same space. The YWG spends most of the time under or very close to the rockwork, where both my previous LMB and current Starry perch a lot, but not deep in the rockwork. That said, my tank is 6'x2'x19" so they have a good bit of room. I also remember having trouble trying to quarantine a LMB with small YWG, but that was in a 17 gal QT with nothing but some pvc for hiding. If you have a good bit of rock and sand, you might try putting the LMB in a quarantine box (or possibly the sump) for a few days and then reintroduce. If you don't have a lot of hiding space, you might want to permanently remove one or the other... maybe remove the LMB and then try to re-introduce one after your YWG is established.

 

[durt.kobain]

I've had both a LMB and currently have a Starry Blenny with a YWG in my DT, and they completely ignore each other and don't occupy the same space. The YWG spends most of the time under or very close to the rockwork, where both my previous LMB and current Starry perch a lot, but not deep in the rockwork. That said, my tank is 6'x2'x19" so they have a good bit of room. I also remember having trouble trying to quarantine a LMB with small YWG, but that was in a 17 gal QT with nothing but some pvc for hiding. If you have a good bit of rock and sand, you might try putting the LMB in a quarantine box (or possibly the sump) for a few days and then reintroduce. If you don't have a lot of hiding space, you might want to permanently remove one or the other... maybe remove the LMB and then try to re-introduce one after your YWG is established.

Thank you I appreciate the detail! I will give that a try for sure if I don’t remove the YWG before.

 

[Fishbird]

I've had both a LMB and currently have a Starry Blenny with a YWG in my DT, and they completely ignore each other and don't occupy the same space. The YWG spends most of the time under or very close to the rockwork, where both my previous LMB and current Starry perch a lot, but not deep in the rockwork. That said, my tank is 6'x2'x19" so they have a good bit of room. I also remember having trouble trying to quarantine a LMB with small YWG, but that was in a 17 gal QT with nothing but some pvc for hiding. If you have a good bit of rock and sand, you might try putting the LMB in a quarantine box (or possibly the sump) for a few days and then reintroduce. If you don't have a lot of hiding space, you might want to permanently remove one or the other... maybe remove the LMB and then try to re-introduce one after your YWG is established.

I think the key here is space. Your DT has a 1,728 sq in footprint and presumably lots of rock for hiding spaces and burrows and finding food on. From what I can see online the interior dimensions of the display portion of the biocube are 16 x 20 so that tank has 320 sq in of space. Your tank is 5.4x the size of the biocube so it makes sense to me that you can keep those fish together without issue.

 

[muzikalmatt]

I have a bicolor blenny and a YWG in my similarly sized tank (IM Nuvo 40) and I think the fact that I have the YWG paired with a pistol shrimp keeps them out of each other's territory. The goby sticks with the shrimp underneath the rockwork in the shrimp's burrows which allows the blenny to have the upper rockwork to himself. Generally I wouldn't recommend adding livestock to try and deal with an existing aggression problem, but adding a pistol shrimp might give the goby a place where the lawnmower benny can't get to him. (Plus, it's a really cool pairing seeing the goby and the pistol shrimp work together.)

Another variable is that the goby was added well before the blenny so he had his territory established already. Plus, I think bicolors are a bit more docile than the lawnmowers due to them being smaller.

 

[Crashjack]

I think the key here is space. Your DT has a 1,728 sq in footprint and presumably lots of rock for hiding spaces and burrows and finding food on. From what I can see online the interior dimensions of the display portion of the biocube are 16 x 20 so that tank has 320 sq in of space. Your tank is 5.4x the size of the biocube so it makes sense to me that you can keep those fish together without issue.

Agreed, but I think it is very possible to keep both in a smaller tank. However, I think the best chance would be to add the LMB after the YWG is well established.

 

[najer]

I have 2 jewel blennies in my sump that have killed fish, you need the goby out asap in my opinion.