Can't Keep Anything Bigger Than A Endler :(

[ponyo]

I have had my 2 main tanks, 15gal and a 10gal, set up over a year, I didn't know about cycling so the deaths in the first few months were due to being in a fish in cycle. My tank has a high ph of about 8, I test water every week and have nearly always have good readings, if I don't then I do a water change immediately. I do water changes once a week. I think the temp is usually about 25c.

I can't seem to keep anything bigger than an endler alive though. I have mostly had platies that maybe last 4 months. I tried 2 honey gouramis and a blue ram (which I now know probably needed a bigger tank, sparkling gouramis (started off with 6, only one survived).

In my 60l I have 5 endlers, 2 pygmy corys, 3 oto cats and did have 2 platies until today. I've had the corys for at least 9months so it seems it's mostly the slightly larger middle dwelling fish that don't seem to cope well in my tanks.

I have 2 betta tanks which are fine, one has a chilli rasbora in and had no fatalities.

What am I doing wrong? I've shut down my 10gal as it only had endlers which are now in the 15gal which I know is slightly over stocked now but I've upped the water changes and have a fluval u2 filter.

 

[N0body Of The Goat]

It sounds like a combination of inappropriate (delicate) fish for your hard alkaline water and overstocking. Under normal long term plans, a 60l would be reasonably stocked with the 5 Enders and the 3 Otos.

It is not just about having 0 ammonia and nitrite, it is also about things like nitrate levels (liquid test kits are awful for accurate readings); not overfeeding (which will cause even greater nitrate rates if increase); stress induced illness from ovecrowding especially with fiesty fish such as Platties etc.

When was the last time you dismantled your U2 filter and cleaned the sponges/biomax in removed tank water, plus removing the impeller from its cavity and cleaning both with wet cotton buds? These U-series internal filters need this at least every other week to maintain their efficiency.

 

[ponyo]

Until last week the 60l has only had 3 ottos, 2 corys and 2 platies, various ones as they have only lasted a few months.

I clean the filter media every month in tank water, maybe I should be doing it more often then. I haven't cleaned the impellor, will have to do that too, didn't realise that I needed to do that.

I didn't really want smaller fish like endlers and we chose the platies so there was 1 each for my kids. Maybe I need to rehome the corys and endlers and start again.
I thought platys were fairly hardy fish, are platys suitable for the ph of my tank?

Is there anything else that would be better suited to the ph if I re-home all the fish (except the ottos as I like them to clean the tank) and start my stocking again.

 

[coolie]

I just looked up sparkling gouramis and it seems they live in acidic water, very low PH, if it helps.

 

[N0body Of The Goat]

Platties tend to be fiesty with each other and tankmates, they do far better in a lengthy well furnished semi-aggressive setup, where bullied fish have a chance of respite/escape.

The pH (but more importantly the likely hardness of your water at ~240mg/l gH) of your water is great for most livebearers, but the size of your tank needs careful choice (presumeably ~60cm), as many do far better in a 90cm or even 120cm setup.