2 Wk Old Tank With Fish My Neons Keep Going Missing

[shelaghfishface]

i started my tank 2 weeks ago, got some fish in there, neons to start with, then a siamese fighting fish, and then, a few little ones with rainbow tails (not sure what they called my son got them for me, but will look them up) and then i got a siver shark,and some large blue ones, ( son again), everything is going fantastic , i did lose one neon and i think he got trapped when i moved an ornament, but hes gone to the doctor in the sea,
the prob is when i stared i put 11 neons in and now down to 6.. cant see them anywhere,and i am totally mistified as to whats happening to them..
the shark isnt looking too guilty but he wasnt happy with the food that i was feeding or at least didnt seem to be, but hes ok now hes eating fine and thus no more neons have gone missing.
now you know what im thinking...what do you think??
ALSO ...
my filter has broken down, i got it off ebay now the seller dont want to know( only 1 week old), so i am currently only running my undergravel filter, it has 4 stand tubes, but with 2 air pumps ( suitable for size of tank)can only get 2 to look busy, this has been going on for about 20 hours so far, but have already grossley abused the budget that i had set for the set up.. so im a bit stuck, i definatley cant afford to get it wrong again,
my tank size is 48inchx25inchx 14 inch (app) would i be better getting an external filter to save on this possibly happening again??
and also is it ok to put plant food in the tank just now when its still cycling? as the poor things are being chewed to bits..
ALSO..
i hate the gravel that i have put in,and want to put in something neutral in colour, when should i do this??the guy at the local fish center told me to wait ( i am in doubt to wether further into the cycle would be the right time)tho i have been known to be wrong, and i am brand new to all this fishy stuff tho i love it already, would it be ok further in as long as i gave them something for stress,
i thankyou all in adavance for your advice and i know im going to get some good from you as i have been reading for days what you all say, but only just thort to register..

 

[kpintheshed]

maybe you should post this topic in emergencys. i'm not a expert but the first thing they might say is

did you cycle your tank?
whats the water stats?
how big is your tank? e.g litres
also maybe you should research your fish in the future because if your tank is too small the fighting fish and the silver shark may end up fighting because they are territory fish so alot of hiding places will be good. oh yeah a silver shark grows upto 13 inches (33cm). the neons are properly being eaten by the siamese fighting fish or shark.

How big is your silver shark?
for the other fish try looking in the gallery

 

[shelaghfishface]

maybe you should post this topic in emergencys. i'm not a expert but the first thing they might say is

did you cycle your tank?
whats the water stats?
how big is your tank? e.g litres
also maybe you should research your fish in the future because if your tank is too small the fighting fish and the silver shark may end up fighting because they are territory fish so alot of hiding places will be good. oh yeah a silver shark grows upto 13 inches (33cm). the neons are properly being eaten by the siamese fighting fish or shark.

How big is your silver shark?
for the other fish try looking in the gallery

cant say i cycled as such, the fish shop man told me to fill the tank then add, fresh start (water con)nutrafin cycle( at start then every 7 days till 21st day and i have also added the rec amount when adding new fish,also added safe start(enables instant introduction of fish-tho i left it a week,then put in the 11 neons) I WAS VERY VERY NERVOUS ABOUT ADDING FISH TO THAT LOT, BUT AS HE KEEPS OVER 2,000 FISH HE MUST BE DOING SOMETHING RIGHT ( mind saying that he sells them .. 150 LITRE TANK (very long as a pose to high)
although i have spent hours researching and asking questions i feel like i dont have a clue what im doing, advice can be very conflicting, i know i will pick it up along the way but dont want dead fish to be the resultof my mistakes.also have a lot of plants and hiding places (pots,pretend coral etc)
i did feel quite confident but maybe not now!
my silver shark is approx 4ins long, have spent hours watching him and the siamese and have seen absolutley no signs of trouble,if anything its the rainbow tailed fish that are causing aggro in there, but no signs of nipping etc,at the moment its a very peacefull community,they tend to stay within their own levels except for feeding time, then all seems ok i now have a total of 22 fish ranging in size from shark to neon,and although ther seems to be loads of space in there i dont plan adding any more for exactly the reasons you have given (sharks a growing lad),
i really hope its all going to be ok, maybe i will be lucky and get away with it

have no idea how to put a photo on here, i tried to upload one and it refused and told me to contact admin, that way everyone could see what i am doing

 

[PRW1988]

The possiblility in my mind is that the silver shark is eating the neons. That or the "big blue ones" which could discribe a number of things from Blue discus to Blue gouramis and even a blue oranada goldfish...

 

[Rooster]

Neons shouldnt really be in a tank that young - they probably died, and got scavenged....

 

[faithless1294]

You have a very varied bunch of fish there. for starters i think most likely the silver shark is eating up you neons i have personally seen a silver shark eat a neon in just a few mins... i would also say the fighter may get his fin nipped often (tetras are bad for that). what are the fish with rainbow tails? and what are the large blue fish? it could be one of them doing the damage in the tank...you should prob get a external espically if the tank measurments are as you say.
Good Luck