Author Topic: Questions about Colonies  (Read 444 times)

Online Pilch566

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Questions about Colonies
« on: April 06, 2017, 10:38:37 AM »
I am wondering what exactly constitutes a colony.

I have a newly set up 20 gallon long tank for which I purchased from a single LFS 6 juvenile multies. The multies are all the same size so I am assuming they are all siblings from a single spawn.

Would it be right to say that these 6 constitute a colony? Or is a colony solely made up of a single mated pair and its offspring?

What if the 6 multies I bought form 3 mated pairs and they all had offspring? Would I have one colony or three colonies?

Looking forward to hearing your responses!


Online jerrytheplater

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Re: Questions about Colonies
« Reply #1 on: April 06, 2017, 05:25:39 PM »
Good question. Never considered it before.

What do I think? Once you start seeing breeding those fish that are incompatible will have been kicked out and you have either removed them or let them die. Those that are left will constitute a colony. Eventually the tank will become overcrowded and you will have to remove some. Once out of the tank, they are no longer part of the colony.

In my 30 gallon I have one lone fish on the right side shell pile which I am assuming is a male. The left side is where the breeding occurs and I now have three juvie's that I am hoping will make it over to the right side to provide a mate for the loner. Then I will have two colonies separated by a rock pile in the middle. The right fish defends his shells against anyone else that goes over by him. And as far as I've seen, its only been one fish venturing over by "him".
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Online Pilch566

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Re: Questions about Colonies
« Reply #2 on: April 07, 2017, 07:32:46 AM »
Interesting thoughts!

Anyone else?

Offline Rupert

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Re: Questions about Colonies
« Reply #3 on: April 08, 2017, 01:59:51 AM »
I'll take a swing. It's an interesting question I've never tried to define, and I guess just accepted my answer for my own tank without questioning my assumptions.

Putting aside any species in particular, I'd say a colony is a group of fish working cooperatively in common defense of a shared territory. In the fish I'm thinking of, that cooperative group includes juvenile and/or non-breeding members who don't eat younger members. I think maybe it might be helpful to even consider that a colony has a power/breeding hierarchy.

But then there's a sense of layering that makes things confusing. Like, a single pair with fry wouldn't be a colony. Is a pair with two spawns a colony? Seems kinda weak. I'll suggest that a colony is at least two pairs with at least two spawns each. They may quibble over agreed boundaries, but they accept each other's presence and there is no predation of fry, neither their own nor their neighbor's. To me, then it starts to feel like there is some kind of "colonial spirit" -- hardly scientific, LOL.

Part of it too is the artificial constraints of our tanks. In Tanganyika, you could probably consider a huge shell bed with hundreds of fish one colony--as opposed to the colony of fish in the shell bed many miles down the shore. You've made me really curious about how biologists think about the question. In the space of the lake, would something like a couple pair of fish with some fry in close proximity even come close to a colony? What's the threshold, ya know? And I get that that's the crux of your question, but how is a colony in a 10 gallon tank relative to a colony in a 180 gallon tank relative to a colony in the lake?

I wonder also if there is some sense of genetic relatedness (as you intimated) that may be a convenient idea to us as hobbyists, but that starts to get really confusing to someone like me when confronted with serious genetics science. I imagine genetic data collected at the level of the lake could actually be used to contour colonies, but for folks with a few fish in a hobby tank, LOL, pretty much a whole different level of inquiry with different genetic concerns and implications.

So, hmmm, I think I consider all the fish in my tank one colony. At one point I had ten fish forming three groups...one lone male with shells, two males with shared shells, and one male with three sub-dom males and three females. Then the dominant male jumped out of the tank and died. At this point, I have a lone male, one male with a single female x3, and two males who have started to separate into adjoining groups of shells as they woo the older females from the earliest spawns. Started with 12 young juveniles, lost two to unknown causes and one jumped from the tank. Ended up with six males and three females--not what you'd want for a text book launch. But apart from the expected boundary squabbling, no one has been chased out of the shell bed and the three females have had multiple spawns and the males without females are now working hard to woo a mate. In all honesty, I considered the fish I brought home to put in my tank my colony--which is no real way to answer your question, but a working assumption I can't deny. May help to say my fish are currently in a 40 breeder with enough shells for all the males to have multiples.

What has your experience been with your fish?     




Online Pilch566

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Re: Questions about Colonies
« Reply #4 on: April 09, 2017, 09:03:37 AM »
Hey Rupert, what a great response! Thanks for putting in the time and effort!

I am newbie to shellies hence my curiosity. I picked up 6 juvenile multies for my first shellie tank just 2 weeks ago. Of the 6 a couple have started digging around the shells a little bit. They display for each other and chase a little but for now it looks like play more than serious territorial or mating behavior.

I assume the 6 are siblings from a single spawn (because I bought them at 1 LFS, all the same size) so I am interested to see what happens when they start spawning. It would be really neat to see them all work together to keep the julies away from the fry!


Online Pilch566

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Re: Questions about Colonies
« Reply #5 on: April 09, 2017, 08:17:31 PM »
What a difference half a day makes! My multies have gone from playful jostling of each other to lip lock fighting! Of the 6 in the tank I observed 2 pairs majorly brawling. Not too happy about this new development. 

Offline Miles44

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Re: Questions about Colonies
« Reply #6 on: April 09, 2017, 11:02:53 PM »
I think it is just as simple as it's definition.  A group of organisms, of the same species, living closely together. In your case a small group of multifasciatus living together in your 20 gallon aquarium. And of coarse living together we must agree means they are in some state of harmony. Which of coarse does take some period of time.  In your case it seems the fish are in the process of establishing their specific harmonial balance. The fish digging out territories, males flashing/showing off to females, and males establishing dominance amongst other males. Which are some of the prominent reasons i love multies so much, And shell dwellers in general for that matter.