I’m a relatively new fish owner. I’ve owned fish for about a year now. I went on vacation for 4-ish weeks and let my friend next door take care of my 8 neon tetras. I told him how to maintain my tank and all the essential information like water changes and scheduled feeding/cleaning. Came back and my tank was a disaster. The decoration was completely moved, dust was everywhere, food was clumping up at the bottom of the tank, etc. The picture below is AFTER I cleaned up all the dust and scraped off some of the algae. I’m not sure where to go from here. Would a water change after this long kill my fish? Any help is appreciated.