Pai sei with you guys, this month is my hectic month, been traveling all around , just come back from chiang mai too ><

hi babybb, was reading all the previous post, some of the info the inferno share , is useful. so dont worry much ya, let me sort out ur concern and see:

1st will be buying a accompany hammy for the current 1. for WW and robo, if you plan to get a new companion for them is good also, as they are more socialized  group if we compare to syrian hamster. While for us human we tends to be afraid of lonely ness, but due to our human caring nature, we always like to match each other up, either in pet or friends too. well tht's human instinct.

through my experience , to let a new hammy to join the current hammy is best you clean up the current cage 1st. and put some bedding into a box, then let the current hammy enter the box, and follow by the new hammy. Some hamster when introduce into new environment they will think that oh, a new place , should explore 1st. so this is the time where new companion can be introduce, as they find th new hammy new scent is smth new. But take note, some hammy is tame and dont show aggressiveness, so they will accept the new friends, but if you notice they start fighting, better remove the new fella 1st.

it just take a sec to know whether they are doing good. if they tag along well, then you can rest assure fighting chance is minimal, but once you introduce the new friend, and the current 1 feel so defensive then it is better to separate d.

the 2nd opinion is get a wire mesh , where there is some small hole between each others, and put it in the middle of the cage, make sure no space for them to slip in through and fight each others. So from here you need to prepare 2 water bottle / 2 bowl of food/. It will take 2 weeks time max, for them to get used to each others. Once you see both of them is ok and smell each other without backing out, then is good to mix, as both already accept each others ^^  

Hope some simple exp, is helpful for you. 

2nd question is the bottle leakage, oh buy living world / deluxe mouse, i find this 2 brand is much prefer, no water leakage and easy to use and wash. ^^ if you bottle leaking,  2 way to solve it, fill the bottle max it, and balance th bottle ^^ as this can make sure the pressure is high enough or equivalent to the room pressure .

anything you not sure can pop up to ask, ill still rearing my hamster, and currently going to give for adoption agouti and sapphire total got 6 of them 2 more weeks before released. =D damn cute hahah