7 week old discus fry dieing!

[Daniel.cummings]

Hi Guys,

Had a reasonably good clutch with around 160 fry, at about the 6 week mark, I started having the odd death.

Now around 7 to 8, I only have 13 left.

WC around 70% daily, sometimes twice.

Fed BBS and freeze dried blackworms 5 or so times a day.

No signs of flukes but have done PP treatment a few times to see if it helps.

I'm thinking maybe worms or something?

[jeep]

Unfortunately, this is the age where many people begin to see die-offs in their spawns, so don't think you're alone. Your feeding and water maintenance routine seems very good, but two main causes can be bacteria, water quality and flukes. All can cause bacterial gill infection that can cause die-offs. Have you noticed the behavior of the fry during this time? Do they turn black or do they slide along the bottom of the tank? Are they still with the parents during the die-offs?

What kind of filtration are you using and how big is your tank? A large spawn can produce a lot more waste than you may realize.

Have you treated the parents for flukes prior to spawning? Eliminating flukes from the parents will eliminate the possibility of flukes in the fry, which should point to overall water quality being the issue despite your large water changes.

You said you started with 160 fry? That's a very large spawn and you may have to increase your water changes, possible double them to 70% twice per day depending on the tank size. When I'm raising even a smaller spawn I do water changes twice daily and sometimes 3 per day, and whether I'm lucky or doing the right thing, I've never experienced this type of die-offs. I also clean the filters every 2 or 3 days because uneaten bbs can be sucked into the filter and produce ammonia when they die and begin to decay. Even trace amounts of ammonia can be lethal to fry.

Let's see if others may have additional ideas that may help...

[AquaticNerd]

PP treatments can be very hard on discus fry. My first thought would be that the concentration was too strong for them, it burned/damaged their gill structure, and then they slowly started dying off.

Have you confirmed flukes? What about the parents, did they go through any kind of QT procedure such as Al's QT Procedure, where discus are cleaned of any potential worm/parasite/etc?

[jeep]

PP treatments can be very hard on discus fry. My first thought would be that the concentration was too strong for them, it burned/damaged their gill structure, and then they slowly started dying off.

Agreed! Also, using PP at such an early age can damage the immune system.

I prefer to use prazi to treat for flukes...

[brewmaster15]

I think alot of fry die offs at this age are the result of water quality and ammonia/nitrite spikes. Even a tiny spike can damage fry gills. Ammonia burns and impedes oxygen transport and waste excretion, and Nitrites are even more insidious as they accumulate in the fish, and as they climb they cause brown blood disease, basically interfere with oxygen transport by hemoglobin. The problem is it takes longer for fish to clear Nitrites from their system than uptake them so they accumulate these faster than they get rid of them. Poor water quality can have a cumulative effect on health and just overwhelms the fry making them more susceptible to higher bacterial loads as well...its really a perfect storm, IMO.

[Daniel.cummings]

Thanks so much for the responses!

I've only recently gotten back I the hobby after a 10 year break.

They are in an 80l bare bottom tank with sponge filter, nothing fancy at all.

The PP treatment was just an attempt to save them but had no effect and continued losing tla handful each day.

None of them show signs of flukes, they seem very active and healthy and then just die, they go a bit darker for a day and then sort of start swimming with no energy of that makes sense

I've got to other pairs with eggs at the moment and hoping to really get to the bottom of it

Perhaps it is just water quality and need more WC, i feel like i already do alot though

[Daniel.cummings]

Quick photo of the remaining fish

[Daniel.cummings]

And a current one slowly dieing, gills seem to work but look very pink

[brewmaster15]

I dont know if this is the cause but It may help to really wipe down the tank walls before your water change and clean that sponge. Have you tested for ammonia before your water changes, Are you using aged water ? Is there a reason for the bag media?

I like to use two sponges in my fry tanks so I can alternate cleaning and Be sure theres adequate filtration. How often do you clean that sponge?

how are you feeding the freeze dried blackworms?
Al

[Daniel.cummings]

I do usually have it much cleaner, I've been lazier the last week with the wall and floor wiping, basically because they keep dieing haha

I haven't actually tested for ammonia, it's a well cycled tank and I figured with the amount of WC it would be an issue?

Freeze dried blackworms in cubes on the glass, they seem to really devour it

The media bag I just had and thought it couldn't hurt, some additional surface area for beneficial bacteria, it gets a rinse along with the sponge say once a week

[brewmaster15]

I do usually have it much cleaner, I've been lazier the last week with the wall and floor wiping, basically because they keep dieing haha

I haven't actually tested for ammonia, it's a well cycled tank and I figured with the amount of WC it would be an issue?

Freeze dried blackworms in cubes on the glass, they seem to really devour it

The media bag I just had and thought it couldn't hurt, some additional surface area for beneficial bacteria, it gets a rinse along with the sponge say once a week

I think this may be the culprit.. rinsing that sponge weekly when you are feeding fry is really not enough even with the large water changes especially since you only have 1 sponge in there. Its really not good enough for fry


hth,
Al

[Daniel.cummings]

Ok awesome, just confirming ammonia is zero so that's good news!

Should I start giving it a rinse with every WC, in some old tank water?

[Daniel.cummings]

I've just given them all a good wipe down inside and done WC, the middle tank are on eggs so I didn't want to disturb the cone so I'll clean behind that another day

It's so disappointing to see the die off after nearly 2 months

If it is the filter issue, any ideas why they didn't start dieing off straight away, or is it because of their increase in size, more food, more waste etc.?

[brewmaster15]

When fry are tiny and just feeding off parent slime and some bbs the amount of waste is tiny .. as the fry grow they eat more, you feed more and they generate more waste. They also make more of a mess when feeding on foods other than bbs so you have to really stay on top of tank hygiene.

I would suggest adding a second sponge filter to the fry tank and if you can age the water do two water changes per day.. . rinse sponge lightly daily. ...you can not change too much water on fry but you can easily change too little.

Fry die offs are always a hard thing to deal with, frustrating when we lose them after all that work. Always question your water quality and tank maintenance first when they start.

Hth,
Al

[jeep]

80L is a 20 gallon tank, which is pretty small. I would suggest breeding them in a larger tank then moving the fry to an even larger tank as they grow, along with increasing the cleaning maintenance and water changes. 115L or even a 150L tanks are much better for breeding.