The Big Kill (with CO2). Was - D*mn it. Damselfly hatched in tank.

cheesehead · 02-14-2013, 12:59 AM

I'm re-starting my 200 gallon heavily planted tank - high light with moss, swordplants, anubias, hairgrass. I'm trying to make it more of an ecosystem than a "fish tank" - I'm growing all kinds of critters in it right now (cyclops, daphnia, MTS, worms in the substrate, etc.) Once I get it all stabilized I'm going to add just a couple of small cichlids, probably rams, & let them go to town & see where everything stabilizes.

Right now the tank is in the "extreme green water" stage. Which is OK, because I've got daphnia & cyclops in it.

Problem is I opened up the cover today and found a newly molted damselfly.

Not the kind of critter I wanted in the tank.

It obviously hitchhiked in on some plants I put in the tank, either as an egg or larvae (along with the cyclops and lots of other small crawlies I don't mind).

I don't know if I've got more. I have no fish, and so I suppose I can just wait until any larvae hatch and die in the canopy. But there's no way I could ever see them or catch them if they're in the larval stage, even if I didn't have green water. Too many plants & rocks.

Or should I just remove enough of my invertebrates to restock and just wipe out all (animal) life in the tank? If so, how?

xdestry · 02-14-2013, 01:05 AM

Do you have a co2 canister? If so just run it on max for a few days and everything will be suffocated

cheesehead · 02-14-2013, 01:11 AM

Quote:

Originally Posted by xdestry

Do you have a co2 canister? If so just run it on max for a few days and everything will be suffocated

Hmmm... that's an appealing option. Won't hurt the plants... Running on "max" I'd probably drain my cylinder - any idea about a target CO2 concentration? I can set the controller to regulate to a specific pH & CO2 concentration...

It would also help me get rid of the pond snails whose eggs apparently also hitchhiked into the tank.

xdestry · 02-14-2013, 03:08 AM

Not sure of a specific concentration, but a 200 gallon is pretty large so you might have to run it pretty high to get it to levels where nothing can breathe inside.

wastewater · 02-14-2013, 04:53 AM

I had the unfortunate experience of damselfly nymphs in a shrimp tank. Shrimp were happy and reproducing like rabbits, but the population suddenly (drastically) started 'going south' in a matter of two months. Could not figure out what was going on until I removed a large clump of needle leaf java fern. I decided to shake the clump out over an empty bucket just in case any shrimp were trapped inside the giant mass of fern. To my surprise, a DF nymph ended up in the bucket. Bingo ~ figured out why my shrimp population suddenly declined.

Definitely some tough critters. From my understanding, they can remain in the nymph stage (underwater) for a year or more until fully grown. I ended discovering a few more throughout the fishroom and was able to physically remove them. They are experts at hiding within plants, and from what I found out, they do a lot of their predatory hunting at night time. If you do have nymps in your tank, I'm pretty sure they are feasting on your cyclops & daphnia.

I've heard that shelter traps have had some success (e.g., overturned clay flower pots, etc.). Had a friend tell me that crays solved his damselfly nymph problems. Never tried chemicals or CO2, so I don't know if it would help your situation or not (although, if in strong enough concentrations, I'm sure they would definitely "do" the deed - but don't know what other types of collateral damage would result). Maximum CO2 injection sounds like an interesting solution. If you go this route, let us know the result.

hydrophyte · 02-14-2013, 05:12 AM

More than likely there aren't a whole lot more of them. I would just leave everything be and if there are still a few they will just develop like you say and once they molt out as adults and that will be the end. I don't think they would be able to reproduce in there very well.

cheesehead · 02-16-2013, 09:32 PM

Going with the CO2 route... Just took a small picking of snails and enough other critters out & put them in their own 55 gallon tank. My own little ark.

With luck I'll get rid of the pond snails that have also hitchhiked into the tank.

02-14-2013, 12:59 AM	#1
cheesehead Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Jun 2007 Location: River Falls, WI Posts: 33	The Big Kill (with CO2). Was - Dmn it. Damselfly hatched in tank. I'm re-starting my 200 gallon heavily planted tank - high light with moss, swordplants, anubias, hairgrass. I'm trying to make it more of an ecosystem than a "fish tank" - I'm growing all kinds of critters in it right now (cyclops, daphnia, MTS, worms in the substrate, etc.) Once I get it all stabilized I'm going to add just a couple of small cichlids, probably rams, & let them go to town & see where everything stabilizes. Right now the tank is in the "extreme green water" stage. Which is OK, because I've got daphnia & cyclops in it. Problem is I opened up the cover today and found a newly molted damselfly. Not the kind of critter I wanted in the tank. It obviously hitchhiked in on some plants I put in the tank, either as an egg or larvae (along with the cyclops and lots of other small crawlies I don't mind). I don't know if I've got more. I have no fish, and so I suppose I can just wait until any larvae hatch and die in the canopy. But there's no way I could ever see them or catch them if they're in the larval stage, even if I didn't have green water. Too many plants & rocks. Or should I just remove enough of my invertebrates to restock and just wipe out all (animal) life in the tank? If so, how? Last edited by cheesehead; 02-16-2013 at 09:34 PM.. Reason: Change in title.*

02-14-2013, 05:12 AM	#6
hydrophyte Sponsor (View User Tanks) PTrader: (123/100%) Join Date: Mar 2009 Location: Madison, Wisconsin Posts: 9,156	More than likely there aren't a whole lot more of them. I would just leave everything be and if there are still a few they will just develop like you say and once they molt out as adults and that will be the end. I don't think they would be able to reproduce in there very well. __________________ hydrophyte Visit the Riparium Supply vendor forum!

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02-14-2013, 01:05 AM	#2
xdestry Algae Grower (View User Tanks) PTrader: (1/100%) Join Date: Jul 2012 Location: pasadena, ca Posts: 97	Do you have a co2 canister? If so just run it on max for a few days and everything will be suffocated

02-14-2013, 03:08 AM	#4
xdestry Algae Grower (View User Tanks) PTrader: (1/100%) Join Date: Jul 2012 Location: pasadena, ca Posts: 97	Not sure of a specific concentration, but a 200 gallon is pretty large so you might have to run it pretty high to get it to levels where nothing can breathe inside.

02-14-2013, 04:53 AM	#5
wastewater Planted Member (View User Tanks) PTrader: (22/100%) Join Date: Apr 2010 Location: NC Posts: 165	I had the unfortunate experience of damselfly nymphs in a shrimp tank. Shrimp were happy and reproducing like rabbits, but the population suddenly (drastically) started 'going south' in a matter of two months. Could not figure out what was going on until I removed a large clump of needle leaf java fern. I decided to shake the clump out over an empty bucket just in case any shrimp were trapped inside the giant mass of fern. To my surprise, a DF nymph ended up in the bucket. Bingo ~ figured out why my shrimp population suddenly declined. Definitely some tough critters. From my understanding, they can remain in the nymph stage (underwater) for a year or more until fully grown. I ended discovering a few more throughout the fishroom and was able to physically remove them. They are experts at hiding within plants, and from what I found out, they do a lot of their predatory hunting at night time. If you do have nymps in your tank, I'm pretty sure they are feasting on your cyclops & daphnia. I've heard that shelter traps have had some success (e.g., overturned clay flower pots, etc.). Had a friend tell me that crays solved his damselfly nymph problems. Never tried chemicals or CO2, so I don't know if it would help your situation or not (although, if in strong enough concentrations, I'm sure they would definitely "do" the deed - but don't know what other types of collateral damage would result). Maximum CO2 injection sounds like an interesting solution. If you go this route, let us know the result.

02-16-2013, 09:32 PM	#7
cheesehead Algae Grower (View User Tanks) PTrader: (0/0%) Join Date: Jun 2007 Location: River Falls, WI Posts: 33	Going with the CO2 route... Just took a small picking of snails and enough other critters out & put them in their own 55 gallon tank. My own little ark. With luck I'll get rid of the pond snails that have also hitchhiked into the tank.