I'm so sorry for your loss⦠Just a few questions that would help a bit: Did you QT the new fish? What are your water parameters? Did she have any strange behavior before? How long has the tank been set up? Did you cycle it? It sounds like a mystery right now, but sometimes sad things just happen. Maybe it was an internal parasite? Bacterial infections also work quickly--Did she have any abrasions or discoloration?

Hi again Donna, Thanks for the link! I have been out of town, but when I returned there was the start of a soft grassy nest like the blues build. Today, the box is filled almost to the top with sticks on top of the grass nest. Looks like I have a competing species of birds. I'm online now to find out what kind of bird builds this type of nest. If it is a sparrow, I guess it's best to remove it. I'm sure they'll rebuild though. Can you put the sparrow spooker up to help with this or is it only after eggs are laid? Thanks.

My husband thinks if we plug up the hole, the wrens will go to the other bluebird box so we'll just keep taking out the twigs. She builds a perfect circle of twigs morning and night. As I walk back from destroying her work if just look over and say, "Sorry little bird." I know it's for the best. I've figured out a way to stop feeling guilty about it; I just have my husband do it! Plus I keep picturing the destroyed bluebird eggs I've seen from what the Wren's can do. Thank you all for your advice. Now we just need our Blue's to start building!

I would like to update my case. The HOSP made one more attempt (when the wounded BB baby was still alive, but seemed could not compete for food), but that time I noticed that BB parents behaved strange and hesitated to enter the house, though they did not sound very concerned. Just in case I approached the house and stuck my finger in, as soon as I puled it out, the HOSP male flew out and I even touched him, BB parents chased him away. If I knew it before I could catch him. I checked the BB babies and they were fine but scared. I was sure that day the HOSP would not return, The next morning, 2 days later after the first HOSP attack, I found the wounded BB dead and the BB female tried to carry him out. I made her leave the house, took out and disposed the dead BB (smell was already bad). I decided to exploit the smartness of the HOSP against him. As I mentioned he leaned that the spooker was not dangerous, and fishing line was also useless against him. I opened the front wall and left it open to serve as a perch site. Instead I attached two-entry patch and stuck it with a scotch tape. I was certain that the HOSP would be too smart to ignore the sudden transformation of the BB house. Besides the house started looking more scary, like having two big eyes. The other thing I pursued with this transformation is to have emergency exit or entrance, since the HOSP would not be able to block the both holes at the same time. With the 2 holes there was more light inside and I could check the nestlings without opening the door. At first the BB parents were confused, but shortly they figured out their babies were still inside and doing well. As the result I have not seen the HOSP around anymore, the BB parents became more defensive and the three BB babies have fledged yesterday. Now I need an advice or opinion: a) I take the BB house down until I significantly reduce HOSP population. Actually the HOSP infestation was not too bad first, but then numerous young HOSPs fledged from the neighbors house and the area became heavily infested. That house is like the HOSP farm, and at the same time HOSPs would almost never seat on my roof. b) I keep the BB house with the transformed front wall, c) I restore the house to its original shape, where I can set up a trap as needed. Thanks. This post was edited by stal14 on Wed, Jul 2, 14 at 11:24