Two pink streaked wrasses in a 20 gallon aquarium - should I be concerned about aggression in the future?

[formallydehyde]

I ordered a single Pink Streaked Wrasse (Pseudocheilinops ataenia) for my 20 gallon aquarium but the seller randomly shipped me two. One is a bit bigger than the other.

They seem to like each other's company right now but I was wondering if I should worry about aggression in the future. I plan on getting a bigger tank when I move later this year but that's 9 months from now.

I know PSWs are considered very peaceful fish but I wasn't sure if this held true in such a small tank, especially if they both end up being males.

 

[Slocke]

@i cant think

 

[i cant think]

I ordered a single Pink Streaked Wrasse (Pseudocheilinops ataenia) for my 20 gallon aquarium but the seller randomly shipped me two. One is a bit bigger than the other.

They seem to like each other's company right now but I was wondering if I should worry about aggression in the future. I plan on getting a bigger tank when I move later this year but that's 9 months from now.

I know PSWs are considered very peaceful fish but I wasn't sure if this held true in such a small tank, especially if they both end up being males.

Do you have a photo of both? That way we can see if you have 2 males (in which case, you’ll want to separate one) or a female and a male or two females.

 

[formallydehyde]

Do you have a photo of both? That way we can see if you have 2 males (in which case, you’ll want to separate one) or a female and a male or two females.

This is about the best I could where I *think* this is both of them and not the same fish twice.
They mostly hang out in the back together behind some rocks so it's been hard to get a good picture.

 

[i cant think]

This is about the best I could where I *think* this is both of them and not the same fish twice.
They mostly hang out in the back together behind some rocks so it's been hard to get a good picture.

That looks like 2 transitioning females if that is both. It’s hard to tell with the photos though. However, just for the safety you’ll want to remove one.

 

[formallydehyde]

That looks like 2 transitioning females if that is both. It’s hard to tell with the photos though. However, just for the safety you’ll want to remove one.

What am I looking for in terms of sexing them by the way? I'll try to get better photos as they get less shy to confirm.

Also does their aggression start out slow and ramp up so I have a little time to figure out how to separate them or once it starts is it an immediate danger?

 

[i cant think]

What am I looking for in terms of sexing them by the way? I'll try to get better photos as they get less shy to confirm.

Also does their aggression start out slow and ramp up so I have a little time to figure out how to separate them or once it starts is it an immediate danger?

IME, it generally just snaps. They’ll get along then they’ll snap.

In terms of sexing, it’s through the blue in the face and also the vibrancy in the yellow lining and green tail.

 

[formallydehyde]

IME, it generally just snaps. They’ll get along then they’ll snap.

In terms of sexing, it’s through the blue in the face and also the vibrancy in the yellow lining and green tail.

Thanks so much for your advice! One more question: How physically violent is the aggression once it starts? Like is it more showy intimidation/chasing kind of behavior or do they go for physical damage?

Just trying to gauge the urgency of rehoming one since they seem braver as a unit currently and the shipping process was already really rough on them (one of them I actually thought was DOA when I first opened the package)

 

[i cant think]

Thanks so much for your advice! One more question: How physically violent is the aggression once it starts? Like is it more showy intimidation/chasing kind of behavior or do they go for physical damage?

Just trying to gauge the urgency of rehoming one since they seem braver as a unit currently and the shipping process was already really rough on them (one of them I actually thought was DOA when I first opened the package)

Honestly, I’m not too sure how bad it is as I have had a Pink streak that just vanished when I started my trio (I’m unsure of aggression or just not doing well anyway). But haven’t actually witnessed any aggression. If I witnessed any interesting behaviour it was mainly just them staring at eachother doing a ‘stand off’ during courting.

 

[formallydehyde]

Honestly, I’m not too sure how bad it is as I have had a Pink streak that just vanished when I started my trio (I’m unsure of aggression or just not doing well anyway). But haven’t actually witnessed any aggression. If I witnessed any interesting behaviour it was mainly just them staring at eachother doing a ‘stand off’ during courting.

Just thought I would update due to there being so little available info about these guys. You were correct, they did need to be separated and were also correct with how quickly the transition from friendly to aggressive occurred. It was essentially overnight. I re-homed the smaller one, who suddenly started attacking the larger one. Catching him was a long process due to this species' evasiveness and tendency to hide close to overhangs.

It was surprisingly violent aggression too, the little guy started cornering the bigger one and would try to ram him, trireme-style. In one of these charges he injured the big one's fin. He would relentlessly patrol looking for for the big one, who took to hiding all day under macro algae.

Now that the little one has been re-homed, the big guy is doing much better and recovering from his injuries well. He's getting much braver too. I'm naming him Resilience (Rez for short) due to his survival of so many harrowing experiences.

For any smaller tank, pink streakeds definitely cannot be safely housed with conspecifics, in spite of their peaceable reputation with other species of fish.