Lawnmower Blenny and Diamond Watchman Goby

Jesterrace · Apr 17, 2018

I currently have a Diamond Watchman Goby in my tank and am considering getting a lawnmower blenny for personality and an attempt to keep my algae under control. I have a 90 gallon tank with roughly 85lbs of live rock in the tank and was just curious if anyone has had success keeping these together since they have a similar shape and I know that both can be territorial/aggressive with fish of similar shapes.

eatbreakfast · Apr 17, 2018

They usually don't bother each other. Lawnmower blennies choose to stay on the rocks, diamond gobies stay on the sand.

JaimeAdams · Apr 17, 2018

Yeah, what he said, they should be fine.

vic5hands · Apr 17, 2018

both have been in my tank since December. 210 gallon

Jesterrace · Apr 18, 2018

Glad to hear. I figured they would probably be okay but know they can take issue with fish of a similar shape.

eatbreakfast · Apr 18, 2018

Jesterrace said:
Glad to hear. I figured they would probably be okay but know they can take issue with fish of a similar shape.

They take issue with fish that occupy their niche more than shape.

mystersyster · Apr 18, 2018

Just an FYI, don't expect your blenny to eat any macro algae. IME they typically eat micro, film algae.

Jesterrace · Apr 18, 2018

mystersyster said:
Just an FYI, don't expect your blenny to eat any macro algae. IME they typically eat micro, film algae.

So they won't eat hair algae? That is my primary concern as I appear to be going through a green hair stage at the moment. Also, I do plan on adding a coral beauty dwarf angel later, could the two of them have issues since they will both graze on it for algae?

mystersyster · Apr 18, 2018

I doubt blenny and dwarf angel would clash. As for eating hair algae... there is a slight chance but I would not count on it whatsoever.

Jesterrace · Apr 18, 2018

mystersyster said:
I doubt blenny and dwarf angel would clash. As for eating hair algae... there is a slight chance but I would not count on it whatsoever.

I may pass on the algae blenny then. I have heard that Sea Hares are effective but would starve after helping me get things under control and my Melanurus Wrasse might take a liking to it (it periodically eats my snails and hermit crabs). I have also considered one of the small bristletooth tangs (although it and the coral beauty might take issue with each other since they are the same shape).

eatbreakfast · Apr 18, 2018

Algae blennies eat some hair algaes, just not all types.

Seahares are an excellent algae eater. They are usually too big for a melanurus to harass.

Michael Llabona · Apr 18, 2018

Yeah no guarantee it will eat GHA. They should be fine together. I actually have problems with my diamond and my kole Tang. Never any damage, just harrassment.

mps026 · Apr 18, 2018

Turbo snail will clean up that algae for u.

CindyKz · Apr 18, 2018

I have a diamond goby and molly miller blenny, which I think is similar to the lawnmower, in a 75 gal with no issues. They ignore each other.

shifty2427 · Apr 18, 2018

mps026 said:
Turbo snail will clean up that algae for u.

+1 on the turbo snails, I had an outbreak of GHA and the lawnmower blenny didn’t even make a dent on the algae went to the local fish store and purchased 20 turbos and no kidding within 4 days there was no GHA in sight.

RobertP · Apr 18, 2018

My algae blenny ate hair algae like there was no tomorrow. He was fat as long as I had gha in the tank! The problem with him was he ate all the algae out of the tank and then starved to death because he would not eat anything else I gave him.
My starry blenny didn't like the algae blenny but there was enough room that they could stay away from each other. Starry wont touch the gha but does nip at the rocks and will eat norri!

IamBennett · Mar 30, 2019

Just added a diamond goby to my tank. I've had my lawnmower in for a couple of months and he's ticked! He's chasing the goby all over the tank. Hopefully this goes away quickly... BTW my lawnmower was one of the first additions to a very neglected tank that I took over and was completely covered in GHA. He ate all of it within a couple of weeks

jabberwock · Mar 30, 2019

Fish are all different. My LMB ate the heck out of GHA and tried to kill my yellow watchman goby all day long....

HOOPDEEZ · Mar 30, 2019

I have a blenny that is great at eating algae, but a total jerk. He started picking on my pentail wrasse and made him smack against the lid so hard he permanently damaged his eye. So off to the refugium he went. Some blennies can be real jerks it turns out

erikaakire · Sep 14, 2022

IamBennett said:
Just added a diamond goby to my tank. I've had my lawnmower in for a couple of months and he's ticked! He's chasing the goby all over the tank. Hopefully this goes away quickly... BTW my lawnmower was one of the first additions to a very neglected tank that I took over and was completely covered in GHA. He ate all of it within a couple of weeks

That's probably the problem... lawnmower should be the last addition... they can get extremely territorial... when I got mine he was the last addition and still chased every single fish out of their caves and spaces. He tried to kill my blue dot jawfish,went for the clownfish ( got beat up) i thoughtthe clownfishhad put him in his place but the devil perched in my flame hawks cave, shoving him right out! My poor flame hawk was so confused...(also the most peaceful fish in my tank oddly enough) and it really took him a long while to stand his ground reclaim his cave by chasing the lawnmower out! But the blenny went for the jawfish again. Strangest thing ever is my hawk absolutely loves the jawfish and lays on top of the large rock above her cave. He swam up to the rock and chased the blenny away from the jawfish. I ended up putting the blenny in fish jail, (breeding box) since he had stressed both my jawfish and hawk. Not what I expected when I bought the blenny, but I was a newbie to the hobby and was given very wrong information from a shop that is only interested in money...