The authors provide a list of the alien fish species that have entered the Romanian ichthyofauna fauna and specify the year, place of signaling and the ecological impact of the respective species. Further on, the authors describe some behavioral aspects of the following species: Lepomis gibbosus (pumpkin seed sunfish), Carassius auratus gibelio (silver crucian carp) and Pseudorasbora parva (topmouth gudgeon).

The investigation of sediment morphology and sediment regime is crucial for the initial stages of the hydromorphodynamic modeling of the Lower Danube basin. This helps in identifying significant habitats and potential obstacles that may disrupt the migration patterns of anadromous sturgeon species in the Lower Danube. This investigation involved the analysis of 10 samples, which were collected in equal quantities from specific places where hydrotechnical activities were conducted, specifically the Bala and Caleia branches. The sediment samples were analyzed to determine their morphological and structural characteristics through granulometric assessments. Additionally, three significant parameters, namely, the standard deviation, symmetry index (skewness index), and flattening index (kurtosis index), were used for further characterization.

Aquaculture water was exposed to very low dosages of copper sulfate and chloroquine sulphate in order to observe their purgative effects at minimal concentrations, where both substances are commonly employed for their antimicrobial and antiparasitic properties in fish farming. It was observed that the well-known treatment using cooper sulphate is effective even at a low dosage, while the proposed novel treatment using chloroquine was not. The present study highlights the need of effective treatment while avoiding compromising medicine misusage which greatly leads to host resistance.