I started out about 4 months ago with 12 Demasoni in a 40-gallon tank with some yellow labs. The tank has the bottom 33% of its height rocked, with open space in front.

In the last 2 weeks I have lost 2 Demasoni. I believe both were young males and it looked like they got picked on.

I'm really not sure what my M/F ratio is. Is this God's way of telling me I had too many males?

With only 10 guys left I'm thinking I need to re-arrange rocks and get some additional Demasoni in there to keep the community size large enough.

Right answer or dumb?

I'm also going to do a water change, since I've gotten behind.

Thanks for any advice you can give!

Don

Don, dont beat yourself up too badly. Your changes will help and they are proactive steps to try and ensure a better harmony among the fish- but truth be told- Demasoni can be difficult sometimes. They are a very aggressive species. More often than not, you find those that keep them with no problems, others have a nightmare on their hands due to their aggression.

My experience has been that male or female- the dominant ones will pick on whoever is around. Heavier rock cover is often the best solution. This may seem controversial but... In the winter months, lowering the heater to a colder water temp seemed to pacify their aggression quite a bit. (I dont mean to freeze them, but slowly lowering the temp to around 72-75 degrees can actually help them coexist)

Let me know how you make out Tres Bien!

Interesting tip, Les, about lowering the temp to 72-75.

I understand what this does to the metabolism of the fish, but
could there be any long term effects on the fish?

Just wondering out loud!

I can tell you that they wont grow extremely quickly. What temp do you have them at now? 82/84?

Drop it to 78 and see?

I meant to ask Larry if the temp changes the deeper you dive in Malawi the way it does here. Are these fish collected in slightly cooler waters?

If you have any reservations, definitely dont lower the temp. Its just a trick I have used during the winter time, seems that they grow accustomed to each other and when the summer comes, the tank warms but there is no aggression. Similar to growing an entire tank from juvies together- when they grow up together there is generally less aggression.

Lowering the temp will decrease aggression, but it will also slow down their growth, too. I tell people to do it all the time when they need to work on their stocking before they wind up with just one fish - at least until they find a home for the terrorists that need to go!

Most people will tell you that male/female ratios don't matter with demasoni, hence the large group. I disagree.

I never lost a one, but I had 5 very happy males and 15 females!

10 is still okay, Don. You don't want to go any lower than that. That may be all you lose. Should you lose anymore, then I would add enough to bring it back up to 15...You've got the space, and this will give you odds of more females.

Another trick I tried may sound crazy, but those 5 males were constantly fighting when I had the rock running all the way across the back of the tank. I took it all out, and made 3 small separate rock piles - one on each end and one in the middle. The 3 most dominant males claimed those 3 piles, and left the others alone.

Sometimes too much rock and too much stress will equal invisible fish!

Kim

I agree with Kim !00%

Don I did what Kim said and it worked for me. I used to have rocks going from one side of the tank to the other and had major dominance issues. I took all the rocks out and made 3 piles and it worked like a charm. It went from constant harrassment to an occasional chase. Here's some old pics....

Before....


After....

I know what I'm doing with my rockpiles next weekend!

My temp right now is at 80.6 F.

The other factor I had not mentioned is that I was away for 3 or 4 days at conferences twice in the last month. I made sure they were fed twice a day the week before I left (about 30 seconds worth a pop) and the week after I returned, but I wonder if this could have raised stress levels. I normally skip food one day a week in all my tanks.

Thanks, everyone for the fast feedback!

Be sure to take before and after pics! I think it's interesting to see how different people scape their tanks.

I believe I'll try that rock work technique when I set up my new tank!

Sounds promising!

I've got minimal rock in all my tanks. I know it's supposed to look more "realistic" to have alot, but I really really like to see my fish and be able to tell what's going on with them.

And, as far as realism goes...We are keeping them in a glass box!

It has worked really well for me, and even reduced aggression and injuries considerably with all my mbuna. I always try to pick out how many smaller piles I need by fish behaviour. If I have 3 males in a tank struggling for dominancy, then I have 3 rock piles...

I'm so anal. blinky

Kim

I had to drive back through San Francisco today so I went to the high quality hole in the wall LFS with the amazing planted tanks and got 5 more Demasoni, with the owner trying for females for me.

That meant that I couldn't wait till the weekend and tonight I re-did my rocks into 3 piles. Hopefully I defined them well enough that the Demasoni consider them to be 3 separate piles, since in a 27"x17" 40G tank I had to make the pattern kind of a triangle and they touch at the corners.

Also moved my Albino Socolofi in with them and the yellow labs to see how that works.

For now I have my Met. Estherae in there to get the orange male away from my orange female Msobos in my 55G... where I've had NO spawns in 9 months. If he misbehaves I have one more tank to try him in before he goes to the LFS.

I'll keep you posted, and hopefully this weekend will have time for pics.

Thanks for all the help!

Don