# Losing battle with Demasoni



## Dego510 (Mar 9, 2009)

I started with 12 demasoni last spring, but lost 2 after a few months. Then bought another 5 a few months later (making 15). A couple months back that got down to 12. Pulled a beat up one 2 weeks ago and another one last night. I'm about to give up on them and move to another species, however, I want to understand everything before giving up.

1) Can I assume that the beat up demasoni are sub-dominant males? The last 2 looked like really nice demasoni.
2) Are demasoni females lighter than males (or not as nice looking as males)? Lighter bars?
3) Can or should I put the beat up fish back in the main tank after it's healed up? Or should I sell to LFS?

The 55 gallon tankmates are 4 acei and 7 yellow labs, so they're not an issue. I also have a lot of holey rock in there. I'm thinking of adding about 10 more demasoni and seeing what happens. Problem is that I can't find demasoni in the Chicagoland area recently.

I love the little guys and knew to expect aggression, but losing 1 or 2 fish every month is craziness.


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## Rhinox (Sep 10, 2009)

I'm sort of going through the same issues with mainganos, to a lesser extent:

1) Can I assume that the beat up demasoni are sub-dominant males? The last 2 looked like really nice demasoni.

I wouldn't assume it. right now, I have 3 male mainganos beating up on a small female.

2) Are demasoni females lighter than males (or not as nice looking as males)? Lighter bars?

Mainganos are colored similarly, and the 2 known females I have are easily the lightest colored mainganos in the tank. When they are all adults, though, they're all supposed to have dark coloring, and I believe dems are the same. When I was in my LFS, I saw a group of young dems and they all looked faint and light colored like my mainganos were. Subdom maingano males in my tank also look lighter colored, but sometimes they darken up. The 2 female mainganos have never really shown any blue coloring at all yet, but I expect they will when they're older.

3) Can or should I put the beat up fish back in the main tank after it's healed up? Or should I sell to LFS?

Its hard enough to introduce a single fish, let alone reintroduce a single fish thats already been exiled once before. I'd return it if its male, or if you can tell its a female, buy some more fish to add at the same time to reintroduce her.

You might try removing the most aggressive dems in your tank, rather than just replacing the ones getting beat up or killed. They are most likely males and if they're causing problems, better to remove them anyways. Keep removing the aggressive fish and replacing to keep numbers/ratio up and eventually you should come to an equilibrium. It sounds like you have way too many males right now, and that is why there is so much aggression.


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## Dego510 (Mar 9, 2009)

I've removed 2 trouble-makers in the past and replaced them, but who knows . . . maybe I replaced them with 2 other males.


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## Sulfurhead (Jul 18, 2005)

Maybe, pull all the rockwork and Dems out of the tank, then rearrange the tank a different way, and put all the fish back in. This may "reset" the boundries and let them re-establish the pecking order? This worked for me with other Mbuna in the past, not specifically my Demasoni though. Mine were all purchased together and everything has been stable for the last year and a half.


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## Dego510 (Mar 9, 2009)

At this point, I'm willing to try anything.


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## DJRansome (Oct 29, 2005)

fishyface510 said:


> Can I assume that the beat up demasoni are sub-dominant males? The last 2 looked like really nice demasoni..


 That is almost always the case for me. In four years I've had one female "victim" fish. To the best of my knowledge. 



fishyface510 said:


> Are demasoni females lighter than males (or not as nice looking as males)? Lighter bars?.


 Not in my experience. Smaller, yes.



fishyface510 said:


> Can or should I put the beat up fish back in the main tank after it's healed up? Or should I sell to LFS?.


Never worked for me, I just sell to the LFS after their nips heal.



fishyface510 said:


> I'm thinking of adding about 10 more demasoni and seeing what happens. ?


That is what I would do and lose the Acei which are a little too big for a 55G anyway.



fishyface510 said:


> I love the little guys and knew to expect aggression, but losing 1 or 2 fish every month is craziness.


Are you sure you are not having a bloat epidemic? It is typical to lose a fish every couple weeks until all are gone.


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## steelers fan (Jun 26, 2009)

yeah add more dems and maybe more rockwork...not sure what kinda rockwork you have in the first place


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## Dego510 (Mar 9, 2009)

DJRansome said:


> fishyface510 said:
> 
> 
> > Are demasoni females lighter than males (or not as nice looking as males)? Lighter bars?.
> ...


Here are some pictures of the lighter demasoni that I believe to be females. They are about 2".




















steelers fan said:


> yeah add more dems and maybe more rockwork...not sure what kinda rockwork you have in the first place


Here's a pic of the rockwork in my tank. Is it enough?


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## DJRansome (Oct 29, 2005)

You have a lot of rockwork, but it appears to be a small number of large pieces with large gaps in between. Maybe if you shift the pieces so they interlock more and make the gaps smaller to fit the size of the fish?

Any fish will lose color if afraid. Maybe your male count is very high? Or those might be immature males, have they stopped growing? They look young. You could start removing the #1 most aggressive and keep going until everyone colors up well.


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## why_spyder (Mar 2, 2006)

This is why I gave up on 'demon-spawn' a long time ago, lol. They are just too abusive to one another.

I like the recommendation to compact the rockwork more - those gaps aren't doing much good to break the line of sight. Those little guys are quick little beasts and making the structure more conducive to hiding and quick getaways is definitely a good idea.

If you aren't busy on Sunday - I would check out the GCCA Swap and see about picking up more _Ps. demasoni_ there if you want more. It's fairly local (depending on where you live in Chicago) and prices are likely to be reasonable compared to many LFS.


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## Dego510 (Mar 9, 2009)

Yes, I'm planning on going to the GCCA swap tomorrow. Hopefully, I'll find some quality demasoni.

Once I add the new ones, I'll move the rocks around to break more lines of sight.


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## dww-law (Jun 1, 2007)

These fish are very aggressive to each other. I would only consider a minimum 25 Ps. demasoni. This will disperse aggression. More is better with this fish.


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## PiePuncher (Feb 1, 2005)

Dude, those are little bitty demasoni.. Those guys should not be killing each other yet. The lighter colored ones are either subs or female. Females will be smaller and can have a slight color difference. My females when older look just like the males for the most part, usually just smaller. Demasoni are tough to keep in large numbers. I know I hear people say you have to have large groups but your large groups will almost always dwindle unless you have constant babies being born, which is usually what happens. You will almost always have losses with demasoni but they breed so quick that the losses are usually not missed. Demasoni are very aggressive twords their own kind. Even in a six foot long tank I have had problems having more than one LARGE male in a tank. I have kept demasoni for about 6 years now and will no longer keep more than one large male at a time.
Your tank is very new, at least it looks like it. Deaths could be caused by tank not being cycled or bloat.?. Are you cleaning out all your filters at once or cleaning one at a time? Just wondering. 
Your rocks are very white and in a mature tank, it would take many plecos to keep your rocks white and it would take a power washer to get them as white as what you have.


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## why_spyder (Mar 2, 2006)

From my very little experience with _Ps. demasoni_ - maturity and size don't necessarily matter when it comes to killing each other off. I had 1" ones sit and chew each other to near death.


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## DJRansome (Oct 29, 2005)

It's weird how different they are. Mine were fine until I'd had them 8 months and then the aggression became a problem. Mine don't die, but I do have to remove sub-dom males regularly to keep the tank healthy. I usually have at least 3 dominant males at any given time, it's when the number climbs higher that someone gets rejected.


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## Dego510 (Mar 9, 2009)

Ok, so I picked up another seven 1.25" demasoni at the swap yesterday (making a total of 17 demasoni). Before I added them, I re-did the rockwork based on DJRansome's popular layout diagram, did a 50% water change, and released the new additions on one end of the tank as food was dropped on the other end.

The main aggressors actually calmed down a little and no one was chasing the new guys. I think that having 17 demasoni zooming in and out of rocks will help spread out aggression.

I also feel that the new rockwork layout has helped spread fish throughout the tank.

Time will tell if this has truly worked.


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## phorty (Oct 30, 2009)

Hopefully it works out for you because your tank is gorgeous. The color combo of the fish is very striking and looks great against the white rocks and sand. Update?

I've been to the swap a few times, its good to hear you find some dems there. I picked up a few Angels and Rams the last time. Side question, where did you get all that rockwork? Was it local?


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## srook23 (Feb 21, 2009)

I've had similar problems with dems in the past. What I've done the last couple times is buy about 10 or so more than what I wanted to keep in the tank long term. They seemed to kill a few off in the beginning...I normally have lost about 10-15 depending, but after they get settled in they seem to be fine.

Having the right rock work helps. I went with lace rock instead of holey rock because I wanted to make more caves and whatnot. I have a bunch of rockwork in my tank with God knows how many caves and I still would lose some dems after adding them to the tank.


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## Dego510 (Mar 9, 2009)

Update: After adding the 7 additional Demasoni and adjusting the rockwork, the tank is doing great. It's been 2 weeks and no one is hiding by the intakes. The aggression has gone down A LOT. There is only one male with imperfect barring that shows any aggression, so I might take him out for both of those reasons.

I think that the overstocking has also helped with aggression since there are 17 demasoni, 7 yellow labs, 4 Acei, and 3 Petricolas. I'll just have to keep up with the WC's.

phorty - I got the holey rock from a guy off of Craigslist.


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## justinf67 (Jul 19, 2009)

any pics of the new setup?


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## BlueDevil (Dec 3, 2004)

fishyface510: good for you that your set up is working for you, might i ask what kind of light you are using for your tank, it looks awesome.

justinf67: what kind of fish is your avatar?


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## justinf67 (Jul 19, 2009)

BlueDevil said:


> fishyface510: good for you that your set up is working for you, might i ask what kind of light you are using for your tank, it looks awesome.
> 
> justinf67: what kind of fish is your avatar?


The fish in my avatar is one of my Demasoni. The pic is a bit blurry. I'd like to get some better ones.


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## Dego510 (Mar 9, 2009)

BlueDevil said:


> fishyface510: good for you that your set up is working for you, might i ask what kind of light you are using for your tank, it looks awesome.


I have a blue actinic bulb and 12000K.

Justin - I will try to take a picture tomorrow night. I just spent 1 1/2 hours trying to net a holding Acei. Man do I hate that. I had to pull out a good amount of rocks, therefore, changed the rockwork as a result.


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