Newbie And Need Help!

[Mystery01]

Hi All,
 
I am new to the whole fish thing, I brought a 25Litre tank for my 5yr old son for his birthday, its been cycled for a month now.
 
I woke up this morning and my cory is laying on the bottom on his side frantically breathing every now and then. I straight away did a 40% water change and added prime hoping that it would help but he is still the same this evening  
 
I have a Betta and 4 neon tetras as well as my Cory, i Lost a little sucker catfish last week, I couldn't find him and when i did a water change 3 days ago, i found what was left of him / 
 
Nitrate = 0
Nitrite = 0
PH = 6.5
KH Carbonate hardness = 40
GH General Hardness = 120
 
Temp 26 degrees celcius
 
I have a bubble rock in there 2 fake plants a ship and a piece of driftwood with a plant attached, which is starting to die now, ill add that i have seen an increase in some type of algae, my fake plants are starting to get black spots on them and there is a brown kinda dust like stuff that is built up in the filter and its now starting to build up in the tank, when i cleaned the tank 3 days ago i stirred up the bottom to clean the crap out from it.
is there anything i can do to try and save my cory? he is such an awesome fish, so playful! my son is devastated.
 
TIA

 

[the_lock_man]

Hi, there.
 
I suspect that your problem is probably ammonia or nitrite build-up, and that actually, your tank isn't cycled. A cycled tank has built up enough bacteria to process the ammonia produced by your fish into nitrite, and then into nitrate. A 25l tank is very small, and I would recommend that you remove the cory and tetras, and take them back to the shop. You could, just about, get away with just the betta in there. Many people would say 25l is too small for even a single betta, but I'm being pragmatic, rather than idealistic.
 
Have a read of our "Rescuing a Fish-In Cycle Gone Wild" article in the Beginners Resource Centre, it's a good read and will tell you a lot more detailed info.
 
You also need to buy a liquid drop test kit - the paper strips you appear to be using aren't really accurate enough for the situation you are in.

 

[AmtotheBurr]

Do you have an ammonia test? There should be nitrate showing if the tank is actually cycled and I belive you said that is at 0. I agree with Lock, on all points. And the betta is fine in that size tank but the other fish aren't appropriate for such a small tank. The neons need more space and are best kept with more than 4. I don't know much about corys.
I know this is hard and I'm sorry your son is losing his fish.
The API master test kit has been awesome for checking my tank while it's cycling. If you don't have a test kit yet I would recommend that.

 

[Mystery01]

Thank you, He is still trying to pull through, but no better than yesterday, ill take a water sample into the shop and get a proper reading and info. The lady at the aquarium said that corys are bottom feeders so you exclude them from the fish to water ratio? Is this right?

 

[the_lock_man]

Thank you, He is still trying to pull through, but no better than yesterday, ill take a water sample into the shop and get a proper reading and info. The lady at the aquarium said that corys are bottom feeders so you exclude them from the fish to water ratio? Is this right?

 
No, it's not right. Yes they are bottom-feeders, but you don't exclude them from stocking calculations. 
 
Both cories and tetras are shoaling species, in the wild they live in groups that number hundreds and often thousands. This is how they feel safe. It is generally accepted that the level at which they lose count and just assume that there's a big enough group to be safe in is 6, although the more the better. 
 
When you take your sample to be tested, find out the exact levels, in "parts per million", "ppm" or "mg/l" (they are all the same thing). Given that the staff member thinks that bottom feeders are excluded from stocking calculations, I have doubts as to her competence to correctly interpret a set of water test results. I would like readings of ammonia, nitrite, nitrate and pH, and please don't accept any vague "That's fine" or "It's a little high, but not too bad" If she is also using paper strips to test, then I really think you will have been wasting your time.
 
Please have a look at the store for a liquid-drop test kit, and if they don't have any, then look online, Ebay and Amazon are both chock-full of sellers who sell the API Master kit.
 
In the meantime, I would strongly recommend that you change as close to 100% of the water as you can daily. Just leave the fish enough water to swim upright in. Make sure that the replacement water has been treated with a water conditioner (aka dechlorinator) and the temperature of the new water is reasonably close to that of the old water - as close as you can by judging with your fingers, you don't need to get thermometers out, or anything like that.
 
Until you can get sensibly accurate ammonia, nitrite and nitrate readings daily, you are going to continue to have problems.

 

[Crablegs]

Agree with pretty much everything above . Tank is very small so any problems will be magnified much quicker. Agree with Lock-man . Water defo needs oxygenating. What type of filtration do you have ? Corydoras should never be kept alone as they are a very sociable shoaling fish . Your shop should be giving you more info when you buy the tanks . If not find another one !!!!

 

[CristianMoya]

how do i post i cant find the button or the help haha

 

[fluttermoth]

how do i post i cant find the button or the help haha

 
You posted; you just need to wait for your first post to be approved (it's how we keep the spammers out)

 

[RainboWBacoN420]

The loosely followed rule of thumb is one inch of fish per 1-2 gallons. You must take into account of what the maximum size of the fish you're getting will be. I usually like to stay under the limit when it comes to stocking, or I take the action of making sure everyone can have a place to hide away from all the other tank mates. 
 
Also, your sucker fish, I'm not sure if you mean a pleco or what, if it is a pleco, he should be provided with much more than 25 liters, plecos also have a very big bio-load no matter what the size is. Which could easily result in a fast build up of toxic ammonia. I would also recommend you isolate the betta into his own personal tank of at least five gallons (18 liters), don't be fooled into thinking they can live in those tiny little cups like most chain stores sell them in. They should be provided with a filter and heater just like any other tropical fish.
As little as those neon tetra may seem, they require at least a 10 gallon (40 liters) tank and they are a shoaling fish, so a shoal of five at minimum would be ideal for them.