Fishes Keep Dying Periodically For No Apparant Reason

[melandkeithsfishes]

Tank size: 128 litres fluval tank
pH: 7.2
ammonia: 0
nitrite: TBA
nitrate: TBA
kH: ??
gH:??
tank temp: 28 deg
Fish Symptoms (include full description including lesion, color, location, fish behavior):
Volume and Frequency of water changes: 1/3 of water every 2 weeks
Chemical Additives or Media in your tank: only medications added when disease discovered
Tank inhabitants: 2 x large plecs, 1 x small plec, 1 x 3-spot guarmie, 1 x blue large guarmie, 1 x yellow guarmie, 8 x neon tetras, 4 other medium size tetras, 1 guppy - male i think.
Recent additions to your tank (living or decoration): none for 3 months
Tank furniture : 1 x shipwreck, 1 x stone, 4 fake plants, 1 x 'no fishing sign' & 1 x barrel
Exposure to chemicals: none known of
Digital photo (include if possible): will add
How long has tank been running: 1 yr

we have had this tank now set up for a year, and seem to have had numerous problems of fish dying since near the start. a few months after the tank was set up with just some gouarmies (i can never spell that word!) in it, we bought 2 kissing guarmies who died within the week and then bought another one and that died too-so gave up on them. 2 gouramies we have had since we set up the tank and they have been fine. since then we have bought fish in quantities of 3 or 4 at least 2-3 weeks apart and some have survived but a lot have died at some point. the fish seem to die periodically, ie 1 every few weeks.

we gained a few fish back in april from a friends tank who was moving house. we gained the 2 large plecs, a few neon tetras, the 3-spot gouarmie, 2 honey gouarmies and the odd other fish. last week 1 of the honey gourmies went like a balloon and died and the other one is on its last legs (same state). im guessing the cause is dropsy but when other fish have gone like that, ive tried to treat them, but they all died anyway.

we change about 1/3 of the tanks water every fortnight and rinse the filter pads in the dirty water from the tank. we have a syphon which we use to get water out at the bottom of the tank & we do have quite a few snails in the tank which we remove if we can get them. we feed the fish a small pinch of fish food and the plecs about 4 little pieces of their food.

i have bought a testing kit-all have been ok apart from nitrate which is usually quite high.

we are still baffled as to how come the fish keep dying. none of them have ever had babies even though we have frequently bought male and female guppies but none have mated. quite a few guppies have gone 'bent in shape' and then died.

we are thinking about re-starting the tank from scratch-as though its a new tank, but we dont know what we did wrong this time.

has anyone got any ideas on what we could do... H E L P !!!!

 

[WILDER]

Plec are massive waste producers and that why you need to be doing more maintance on your tank, weekly gravel vac and a water change.
Nitrite,and nitrate reading would be good.
Your tank is quite well stocked what type of plec are they, it sounds like to me you need another fitler in your tank, as that fluval might not be able to cope with the load of fish in the tank.
If your nitrate reading is high it definately sounds like you need another filter.

If them guppies had a bent spine and they wasnt born like that sad to say it sounds like fish tb, and would account for alot of fish losses.

http/www.4qd.org/Aqua/disease/tb.html