Why Do Most Of My Fish Keep Dying

[kagey]

Hey everyone, I was hoping the community could help me diagnose my tank. Most of the fish I buy die either 1 week or many months after I put them in. Here is a rough fish history from memory:

55 gallon fresh water
Fluval 305 - bio ring things with bottom shelf plastic pot scrubbers
No live plants
day lighting is 5 hours on 1.5 off 6 on.
First established around last September.

At first I put in 10 mickey mouse platies, I no longer have any left. The last 2 died a week ago. The time of death of all of them was pretty evenly spaced out between December and last week. They all died showing similar symptoms: lathargy, stomach area would get sucked in, a slight hunch back, tail fin would no longer be spread out and healthy looking, dorsal would become spikey (I think due to the slight hunch back). Eventually a dying one would slowing just stop swiming and die. The death process took from 3 days to 7 days.

About a month after I got the first batch of platies, I got 3 more mixed coloured ones from a different store and they still look healthy.

A month after I got the second batch of platies (2 months of tank break in), I got 2 pearl gouramis. One died about 5 days later (I assume because it couldn't adjust). The second died about 2 weeks ago. It might have shown slight lethargy, but nothing obvious.

When I got the gouramis, I also got 3 ottos. 2 died in a week, one is still alive and very fat/healthy. There is plenty of red/brush algae to feed it.

About half a month after i got the ottos, i got 3 albino cories. 1 died in a week. one died after 2 months. the last died about 1.5 months ago. none showed any symptoms.

When the last cory died, I got another 3 albinos and 1 brown speckled one. 2 albinos died within a week, the last albino died in a month, and the brown speckled one died yesterday. none showed symptoms. The cories were probably the most active in the tank.

When I got the second batch of cories, i also got 4 small angel fish. They are still alive and chase each other to establish the pecking order.

Half a month after I got the 4 angel fish, I got another small angle fish and some sort of a catfish that looks like a shark a bit, its light grey with dark grey/black speckles/markings (sorry i forget the exact type). The new angle fish died in 2 weeks without showing symptoms. catfish shark guy is still going strong.

So there it is.. Right now I am left with 3 platies, 4 small angel, 1 catfish shark guy, 1 fat otto.

I don't do weekly water changes... maybe monthly, but my levels are all good and I check them (yes with test tube kits, not the strips) at least bi weekly and they are always fine.
Ammonia, Nitrate, and Nitrite are always on the safest colour.
PH is slightly high, around probably 7.7, no higher than 8.0 (its hard to tell on my high range colour sheet - 7.7 - 8.0 look like the same colour). This is after throwing in some PH down as my tap is around 8.0-8.1.

I don't know what are good ranges for hardness, my measurements are:
GH is 80 mg/L (ppm) CaCO3
KH is 40 mg/L (ppm) as CaCO3

I feed about 6 times a week - 5 flake days, one blood worm / flake mix day. Some days a pellet is tossed down for the catfish. When i feed flake it is gone within 15 seconds.

That is all the info that comes to mind. I hope someone can help me troubleshoot why I can't keep most of my fish alive for long periods of time. Thanks for reading!
Kagey

 

[Corleone]

The symptoms you mention

Define "safest color" for ammonia, nitrite, and nitrate. You gave good details on hardness and pH, but these are rarely stats to worry about - the only time they'd be a concern is if they're significantly different from those at your fish store (common if they're in a different district, but also possibly caused by using pH down).

pH down is also rarely a good idea - using chemicals to muck with the pH also tends to destabilize the pH. The majority of fish, especially captive bred and certainly all the species you mention, will adapt to a steady pH even well outside their ideal range with no problem, worst case scenario they won't be able to breed successfully. However, an unstable pH, even dead in their ideal range, can stress and even shock them. They especiallly don't like the sudden changes - if your fish store has different stats, or similar but aren't using the same pH chemicals you are (which I can pretty much assure you they're not just because of the expense).

There are safer ways to adjust pH if it's critcally needed, but my water comes out at a higher pH than yours and my tanks stabilize at a similar pH to yours without treatment, and I've kept angelfish, keyhole cichlids, and have friends nearby who keep discus in unmodified tap water.

How did you cycle the tank initially?

As for water changes, just because the stats you measure are in line doesn't mean it's safe to skip water changes. It certainly means they're less pressing on the weekly schedule (very hard water also helps - the tank will tend to resist natural pH drops that can come with few water changes), but there's more things going on in the water chemistry that the affordable home tests don't account for, and it's these things that cause the real stress.

So, there's a couple things that could be stressing the fish, and some uncertainty about the important water stats. Stress is an all around killer with fish, it weakens them in general and opens them up to every kind of infection.

I'd post the symptoms in as much detail as you can in the emergency section, there's some people who read there that really know their diseases, but the pinched stomach and hunched back sound like parasites. The tail fin effect you mention is probably fin clamping, which is a general sign of stress or disease. The spiked dorsal fin isn't directly caused by the bent spine, but the fin fraying, which is also a common signal of stress or disease and can also be fin rot, but fin rot can progress very quickly and leave only the fin rays standing up, and can even continue onto the body if not treated.

Not very pressing considering the other problems, but I'd try getting a better ID or posting a picture of that shark catfish. The term could refer to a lot of fish, from the Colombian shark catfish (which can get much larger than your tank can hold) or the iridescent shark (which could get big enough to eat the Colombian), among others. Your passing description could also be some kind of pictus or synodontis or a lot of other catfish, many of which would be fine in your tank but might eventually try to eat the otto. If it is one of the potential monsters, it could cause major problems a few months down the road once you get the current problems sorted out.

 

[Malt_Vinegar]

Ammonia, Nitrate, and Nitrite are always on the safest colour.

You need to elaborate on this part... What is the reading?

Ammonia should be practically non-detectable if the tank is properly cycled.

 

[kagey]

Hey guys, thanks for the replies. By safest colour I mean the first colour on the comparison card that indicates the presence of zero to little of the thing measured.

The initial 10 platies was basically my fish in cycle.

As for water changes, just because the stats you measure are in line doesn't mean it's safe to skip water changes.

Why not? I thought the main purpose of water changes was to remove nitrate? Since my tank is so understocked the nitrate level doesn't really increase.

I'll stop using ph down, but I didnt start trying it until around Feb this year.

The catfish shark looks like it is a pictus judging from images from google. The patterning on mine does not look as spotted as the pictures I've found, but the head features and barbels look like an exact match.

 

[Corleone]

Nitrates themselves aren't very deadly - hardy fish have been tested to easily survive hundreds of ppm. However, long before the time that a lethal level builds up in the tank, you get stuff like nitric acid building up as well, which reacts with the carbonate hardness, and when the kH drops very low, the pH can very suddenly drop (a pH crash, though you're nowhere near that). You also get all kinds of dissolved solids and other waste products (just like us, fish pee and poop isn't just ammonia).

Nitrate makes a good alarm bell, but increased water changes is pretty much the go-to fix all. It doesn't always fix things on it's own, but it's almost always involved in fixing things.

There's one other thing to consider, too, if you're getting a LOT of short lived fish. Do you know anyone else who buys fish from the same dealer as you? There are just bad sellers out there with terrible stock. There's two in my area, and occasionally I'm forced to brave their tanks to get the species I really want, but I've regretted it more often than not. Your problem could be as simple as just finding a better store. Always look for problems at home first, but it's possible it's not entirely you're fault.

If you're cat's a pictus you're in good shape, it's not a monster or tank buster. It might eventually eat the oto, but it's not a dire danger or something to get rid of right away.


BTW, we both emphasized the ammonia and nitrite levels for a reason. "little to none" still isn't that useful. Most test kits have 0.25 ppm as the lowest non-zero measure, and 0.25 is already a level of concern with fish in the tank. Any ammonia or nitrite that isn't 0 is bad, 0.25 ppm is already time to start worrying, above 0.5 may be cause for immediate panic, even though the test scale may go to 8.0 or higher.

 

[kagey]

Coreleone, thanks for the info. I just checked my test kit and all of the lowest colours are 0 ppm for ammonia/nitrate/nitrite. I was at work before and couldn't check.

I'll go with more frequent water changes going forward and avoid pets unlimited for the next couple purchases.

Thanks!

 

[waterdrop]

Agree with Coreleone. Nitrate(NO3) is an alarm bell, but not that much for itself as for other chemicals you are not measuring. In your case, NO3 does not appear to be rising on a steady basis, which is good, but if you are able to make yourself step up the gravel-clean-water-changes you may end up observing that the NO3 level will re-establish itself at a slightly lower level. Besides the NO3, the water changes will be lowering the levels of hundreds of -other- things we don't have the time or money to measure, such as various heavy metals and complicated organic molecules. Its not clear this would turn out to be the difference for you but it could not hurt.

I also agree that trying a different source of livestock might change things and I might also try switching brands or food types, especially for the bloodworm, which can be overly rich in the gut sometimes for some fish. It may be wise to be slow about coming off the pH adjuster, just to lessen the shock but you definately want to be rid of that.

~~waterdrop~~