A bit of help with the Auld folks tank

Bebo stunnah

'm sure some of ye might remember me rom a while back, I'm no stranger to a fish tank (I have 3 but only one is up and running), but since the last time I was on here I've been a bit busy, with looking for accomodation/new car/work, so I've just about been able to keep on top of my own tank! Goldies have eaten all of the one plant I was hoping to re-house into a properly planted tank!

Anyways, this isn't about my tanks, as the title suggests. I was over at the folks home and found that one of the 2 fish that have been in the tank (25/30l) died, A fighting fish. So all that was let was a single Neon Tetra. I told them, if they were planning on keeping that one alive they'd better get it another 3 or 4 buddies or it wont last too long. So the next day I was over and what do ya know they have 5 new fish... 4 guppies! and a form of sucker fish (not entirely sure what one), or as my mum called it a cleaner fish

Now before anybody says it, yes, I'm aware that the tank is now overstocked, its not right and all that... I know. But what I'm askin is does anyone know of an external filter that would be cheap/effective, preferably online as there arent really any locally. I taught them ages ago how to do water replacements to dissipate the chlorine and to stop them from just topping up the evapoated water. The filter on the tank is only a simple hanging filter with mechanical filtration. There is also a few live plants, from my main one which seem to be growing, but there seems to be a kind of green algae like substance growing on it, which I assume is from the lack of filtration or water flow.

I can upload photos at some stage if need be

campo

Can't help with the filter but the cleaning fish sounds like it is a pleco and they get huge if you were able to rehome him I think with a 50% water change a week the rest might be ok , but I am only a newbie others might have better advice

buzz

Sounds like too many fish were added together and if you do a water test you will prob notice a spike in Nitrates. If you do a 20% water change and re test the water.. The growth in algae is most likely caused because over the biological overload.

Bebo stunnah

Haven't tested the water yet but it was an already cycled tank, so I'm not too worried about a spike in nitrates. Like I said, it has live plants in it, which to my amazemen seem to be looking better than ever! I noticed the guppies eating the layer of green algae which had started to coat the leaves of the plant! The algae on the glass seems to be receding too! (not sure what that's down to).

On another note one of the guppies seems to have been attacked. Seems to be some damage to the dorsal fin

Sleepy

A tank cycles to the level of ammonia being generated in it. Adding too much new stock in one go can cause the cycle to kick off again as the level of bacteria in your tank needs time to increase to deal with the increased bio-load.