# Marbled Hatchetfish Deaths



## apistaeasy (Jul 16, 2004)

I have been trying to keep marbled hatchetfish ever since I started up my current South American tank over a year ago. I have probly bought well over 30 of these fish, but they never seem to last long. I know they are fragile fish to begin with, but I think there might be other factors leading to deaths. Tell me what you think!

Possible factors:

Hatchets are high oxygen fish.
I live in SLC @ 4000 ft plus above sea level
I DIY CO2 w/a tight lid. At night when plant O2 production stops, maybe O2 levels drop too much???
I always have my filter set on high, which creates visible air bubbles though...

Hatchetfish like to jump, and get very spooked at night.
I have noticed at night when my lights turn off the hatchet fish freak out! 
What if they are attempting to jump out, and are hitting so hard on the glass it kills them?


What do you think it is??? A factor in my tank, or just wimpy fish?


Thanks, 

Erik

ps, 36 gal B/F S. American tank, heavily planted, diy co2, 93w of full spectrum light, penguin filter w/bio wheel, weekly 5 gal h2o changes w/ RO(but since introducing hatchets, have changed h2o 2.5 times), bi-weekly fert.


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## apistaeasy (Jul 16, 2004)

oh, not that this will help a whole lot....


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## ranmasatome (Aug 5, 2005)

Are you pumping co2 24/7?? Hatchets are relatively easy.. just make sure you got that cover and dont leave your co2 on 24/7. Check you Water conditions


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## trenac (Jul 16, 2004)

Are you making sure that they are getting enough food. They are surface feeders and slow about it. So feeding a floating food is needed. If you have other fish in the tank that are more aggresive feeders they could be taking the food away from the Hatchets. Otherwards they could be starving to death.


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## UniFish (Oct 5, 2005)

I cycled my first tank with Silver Hatchet fish and they are still with me. -- What irony.


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## apistaeasy (Jul 16, 2004)

I am letting my co2 go 24/7, but it's diy aka yeast. The cold temps of the night usually slow the production of co2 down.

I feed them floating flakes, and they have very little competition in eating. my tank is sparce right now, as I only have the school of hatchets, corys, otos, a flagfish, and 3 gold dwarf acaras(more aggressive, but never go to the top of the tank)

My water conditions are fine, like I said weekly h2o changes(2 since I acquired the current school on tuesday). all other fish are strong. 

anybody else have hatchets at elevation? My LFS has trouble keeping them alive too.

silver hatchets are much more robust than marbleds, you couuld expect them to withstand cycling a tank.


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## JanS (Apr 14, 2004)

I don't know how the elevation would affect them, but if your fish store is having trouble keeping them alive too, it could just be weak stock they're getting in.

It is certainly possible that they are offing themselves if they are hitting the glass too hard like you say, too. Maybe try to have a room light on when the lights go out and give them a more gradual fade into darkness. Or, maybe keep a nightlight going near the tank, like you would for a kid who's afraid of the dark?? 8-[ 

That said, I've never had a problem keeping marbles, and the only thing that eventually did them in was finding them plastered to the kitchen floor.


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## apistaeasy (Jul 16, 2004)

The reason I think elevation would effect them b/c they are a high o2 fish. lower o2 @ elevation. How would co2 injection effect the 02 levels in the water w/ a tightly sealed tank? 

my tank is sealed up pretty darn tight, so I wont have any fish jumping out. 

I have been trying to gradually darken the tank, I even have a moonlight LED inside. even once it has been dark in the tank for multiple hours I can look into the tank w/ help from the LED, and the hatchets are always moving around. 

do you think if I made a lid that was several inches above the h2o level it would decrease the risk of them jumping into the glass and offing themselves?


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## fishfry (Apr 15, 2004)

I had horrible luck with marbled hatchets in my tank. I originally purchased 20 of them and a year later I was down to a handful and finally none. Some of the hatchets managed to jump out which boggled my mind since I thought my lid was so secure, I made sure they got plenty of food and the tank was nicely planted with a mild current for them. I don't plan on getting hatchets again anytime soon because it seems to me they do better in larger tanks with more swimming room.


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## apistaeasy (Jul 16, 2004)

so, what was your tank size? 
what size do you think would be better?

I see your in cali, along the coast? at altitude, or sea level? Just trying to find a link...


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## fishfry (Apr 15, 2004)

20 gallon, 100 feet above sealevel? 

I don't have anything to support my hypothesis that they do better in a larger aquarium except personal observation. For a lot of fish larger aquariums can lower their stress level, like tangs that have a propensity to get ick in small aquariums. Moorish Idols are another saltwater fish that along with dietary factors appears to do better in larger aquariums. The healthiest looking hatchets I have ever seen have been in large aquariums, namely the Baltimore Aquarium and in some of Amano's older works. Who knows, I certainly could be way off base?? I would be really curious to hear if anyone has better success in larger aquariums as opposed to smaller ones. Marbled hatchets also don't seem as thick bodied as other hatchets like silver. It is just kind of odd that out of so many hatchets I have none left, yet I still have the majority of my tetras I got at the same time.


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## ranmasatome (Aug 5, 2005)

IF you think its the o2 then why make it harder for them with the co2 injection at night?


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## JanS (Apr 14, 2004)

I have to agree that maybe your 02 levels are getting to low at night with the C02 running all the time. 
I realize that you can't turn DIY C02 off at night, but maybe you could try running an extra airstone in there at night for a week to see if things improve. 
If the O2 levels are really what's causing it, you won't be losing anything by giving them a little extra when they need it.


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## apistaeasy (Jul 16, 2004)

I had two more fish die over the last 3? days. they have both died during the day. I check in the morning, alive and feeling happy, come home from work and there is a shiny fish on its side inbetween my plants.

my school of nine is down to 4, with one looking bad.

I'm just going to take them back to my LFS, and get something else!

Would an airstone help if I'm already seeing bubbles from my filter? (constistent stream of minute bubbles are constantly present)


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## ranmasatome (Aug 5, 2005)

Why dont you just dump an airstone in and just try... what harm can it do?? your fish are dying while you're still wondering if it'll help.. just dump one in and see what happens.. if they still die then return them as you like.


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## JanS (Apr 14, 2004)

It's possible they are even lacking o2 during the day, so I would certainly try the airstone. Even though you are seeing bubbles from your filter, the airstone will help add more O2.

Even if the Hatchets are a little more sensitive to it, it could eventually tax your other fish before their time if they aren't getting enough oxygen, so it's best to try to remedy the problem if there is one.


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