Fish Deaths - Just A Coincidence, Or Something Wrong?

[zipr]

I've been keeping a 30 gallon tank for several years now, and it seems I am losing fish much more quickly than I should, especially when I look at fish lifespan listings

Here's all the specs:
-29 Gallon tank
-Penguin biowheel Emperor filter, I change the filter pad monthly
-Submersible heater that keeps the water at 80 degrees
-A number of plastic plants, and two live plants that I added about a month ago that seem to be doing ok
-A few fake rocks/pots for fish to hide in
-Florescent light that's on a timer for 8 hours a day
-The tank gets a bit of sun every day (beyond my control), though I did tint the side that gets the most sun with auto window tinting plastic (I still get some algae which I try to remove at cleaning)


The water:
-30% water change every other week (w/gravel vacuum), treat new water with Novaqua+ for chlorine/chloramine
-No ammonia or nitrite readings ever
-Ph of around 7.2 - 7.4 (which is the same as it comes out of my faucet, I don't treat the water for pH)


Feeding:
I feed a small amount, twice a day:
-Alternate between Tetra Pro flakes and Spirulina flakes
-Once a week, I defrost a brine shrimp cube and feed them that
-Occasionally (2x per week or so), I throw in a sinking shrimp pellet or two, for the bottom feeders




The fish in the tank now:
1 Red-tailed shark
3 Cory Catfish
3 Otocinclus (added 2 weeks ago)
3 Pristella tetras (part of a group of 6 about added about a year ago)
1 Honey Gourami
1 gold German ram (added 2 weeks ago)
1 Balloon mollie (added 2 weeks ago)

Recently lost fish:
1 Pristella tetra in the last week -- it got really skinny before it died
1 Balloon mollie (added 2 weeks ago, with the other mollie -- no visible signs of anything wrong. Found dead last night)
1 German ram (one of a pair that I added 6 months ago. I bought the other ram to go with it and found it dead 2 days ago -- no visible problems, and it really had nothing to do with the other ram)


So is it just coincidence or am I doing something wrong?
-Is there something in my setup?
-Am I putting too many fish in my tank?
-Should I be controlling pH?
-Could one fish be killing the others? The shark seems to mess with the other fish from time to time, but I didn't notice it going after these particular fish?

Thanks for any insight!
Zipr

Edits: added feeding info

 

[smegforbrains]

The Penguin filter. you say you change the pad monthly?


How many pads does it have? Just the one?


If so, whenever you change it, you will lose all your bacteria

 

[zipr]

The Penguin filter. you say you change the pad monthly?


How many pads does it have? Just the one?


If so, whenever you change it, you will lose all your bacteria

It has one combo filter sponge + activated charcoal that I replace. It's a hanging unit with a biowheel, which I thought was where the bacteria tend to hang out...

 

[zipr]

Anyone have any ideas?

Is there any more info that would be helpful?

 

[drobbyb]

Anyone have any ideas?

Is there any more info that would be helpful?

Never change the pad unless it is literally falling apart. I don't care what the package says. Changing the filter insert is effectively putting your tank back into the beginning of another cycle, and will take 4 weeks or more to complete. If you are changing every 4 weeks, you will kill everything in the tank. Period.

Changing the pad is a terrible thing to do.

 

[zipr]

Anyone have any ideas?

Is there any more info that would be helpful?

Never change the pad unless it is literally falling apart. I don't care what the package says. Changing the filter insert is effectively putting your tank back into the beginning of another cycle, and will take 4 weeks or more to complete. If you are changing every 4 weeks, you will kill everything in the tank. Period.

Changing the pad is a terrible thing to do.

So how long does the activated charcoal in the filter last?

This is the kind of 'pad' I'm talking about:
http/www.thatpetplace.com/pet/prod/214089/product.web

 

[rabbut]

OK, remember here Drobby that the pad is chemical and mechanical filtration primerily (though it does do a small amount of biological filtration also), with the bio-wheel doing the biological filtration as the OP says Changing the pads just racks-up costs, it should not negatively affect the tank too much Carbon lasts 3-7 days depending on who you ask, so realy, to keep it active, you need to be replacing the carbon pad weekly I'd cut the next one open, ditch the carbon and add another sponge to it. This creates a pad that only needs replacing once every few years, when the sponge deforms, falls appart or becomes un-cleanably clogged. To keep the filter running then, you just clean out the sponge in old tank water

What is the nitrate reading?

What is your waterchange and gravel cleaning regiem like?

With nothing specific to go on, it could be anything at this stage. Are you noticing any raised blood vessles or swellings on the bodies?

All the best
Rabbut

 

[drobbyb]

I disagree. I have had one of those filters for the past 8 years. It was the first filter I ever bought. Back then I wasn't great at keeping fish. I did understand about the nitrogen cycle and such as back then fish in cycle was the thing to do. I killed a few fish until I learned that the Bio-Wheel alone isn't enough.

I want to add that Rabbut's idea about cutting the cartridge open and putting bio media in is a great idea and should solve the problem.

 

[backtotropical]

Hi Zipr,

Good informative post up there. It's not often we get those. Usually we need to squeeze the information out of people.

Seriously though, I agree that replacing the carbon filter pad with a filter sponge is a good idea, as it won't need replacing and will add to biological filtration capacity. However, you mention that you have no detectable ammonia or nitrite ever. That's good, and indicates that the filter bacteria aren't the source of the problem.

The first things which strike me are the Red Tail Shark (how big is it?, these guys are well known for harrassing other fish), and you feed twice daily (is there ever any food left over after feeding?, and as Rabbut says what is the nitrate reading?).

If you have all these bases covered already, it may be something like a bacterial infection as Rabbut suggests.

What is your waterchange and gravel cleaning regiem like?

Rabbut, Zipr details this in the original post.

Cheers

BTT

 

[rabbut]

What is your waterchange and gravel cleaning regiem like?

Rabbut, Zipr details this in the original post.

Cheers

BTT

So they do 30% weekly waterchanges should be ample for a lightly stocked 30g, but it would be nice to still see the nitrate readings Sorry Zipr, I'm not used to seeing all that information in a troubleshooting thread, as BTT says we usualy have to squeze that level of detail out of a new poster, so I usualy get lots of time to absorb it. Giving it to me all at once kind of put me into information overload

If you have all these bases covered already, it may be something like a bacterial infection as Rabbut suggests.

Just to avoid a potential future issue, I'd make shure you have a definate diagnosis before treating for anything. To treat internal bacteria, you use anti-biotics. Anti-biotics are fairly indiscriminate and can wipe the filter's bacteria population with a slight overdose. Obviously you want to avoid that risk wherever possible, hence why you need to be shure it is internal bacteria before starting any treatment for it Internal bacteria can move quickly though, so you obviously need to nail the caurse sooner rather than later, so something can be done before it's too late if bacteria are at work

All the best
Rabbut

 

[zipr]

I tested for nitrates last night -- zero.

None of the fish that recently passed looked at all unhealthy, except for the tetra, which had gotten really skinny.

I may try making a better sponge filter as a few of you suggested -- or perhaps putting two in as the filter has space for two.

Since activated charcoal lasts such a short time and is therefore probably not usually doing much for the aquarium -- is it necessary?


Finally, the shark is about 3 - 4 inches.


Thanks for all of the help so far!

 

[rabbut]

Can you get the water tested by another test kit? I doubt that even with a low stocking that they would all be zero, unless this is a realy heavily planted tank? Normaly with a cycled filter, nitrate will be present as a by-product What filter media is in the filter? Just sponge and Carbon? No Zeolite add-ons are there?

I don't run carbon on my tanks, and all are fine

The more media the better IMO, so if you can get more sponge in, go for it

All the best
Rabbut

 

[Syphoniera]

Hi, zipr,
sorry to hear about your losses.
I notice the deaths occurred after you added 5 fish, one of which has died.

... Recently lost fish:
1 Pristella tetra in the last week -- it got really skinny before it died
1 Balloon mollie (added 2 weeks ago, with the other mollie -- no visible signs of anything wrong. Found dead last night)
1 German ram (one of a pair that I added 6 months ago. I bought the other ram to go with it and found it dead 2 days ago -- no visible problems, and it really had nothing to do with the other ram) ...

Certainly, this would have increased the bioload, there's no mention of any additional waterchanges conducted during the intervening period, with these regularly conducted every second week, and only two plants which are unlikely to be large enough to suck up additional ammonia production, so a temporary spike at that time may have been possible.

But apart from this, the fact that the first fish to die became 'really skinny' prior to death indicates a further problem.

There are a number of diseases/parasites which don't necessarily present obvious symptoms, and I'm wondering if any of the new fish brought something in, and/or whether there may nave been some pre-existing disease or other issue.
Was the tetra which died skinny prior to the addition of the new fish, or was this more of a sudden thing in the week between this introduction and the Pristella's death?
Fish don't generally seem to lose weight rapidly, and such a drastic change would be very scary.

I believe Red Tailed Sharks tend to be somewhat aggressive toward other fish, and I know I lost some fish which had managed to keep going long-term with a mycobacterial infection but which weakened to the point of being unable to swim properly and having to be put down after suffering the stress of bullying by some fish - although this was not very evident, despite habitual fish-watching of the tank which is right beside my bed, and the seemingly unlikely (and evidently sneaky) culprit identified mainly by luck.
Stress weakens and makes the victim susceptible to disease, and such bullying may even prevent their feeding.
Perhaps somebody familiar with the behaviour of Red Tailed Sharks could comment?
(As had occurred in the interim.)

But there may have been a number of factors involved, and if any are capable of identification and improvement - i.e. treatment/relocation of territorial/aggressive fish/increase in ammonia-absorbing and shelter-providing live plants - it may be important to review these and see what can be done.

Just thought I'd suggest these as potential factors, as they hadn't been mentioned at the time of writing, although I wound up wandering off last night before finishing; just refreshed the page, and some new comments have.
But I'll add this anyway, just in case anything might trigger something.
It's such a nervewracking situation for a pet owner...
I do hope everyting works out OK now.